Is the pandemic masking waste management? – A review on fallout of the COVID-19 viral contagion

ABSTRACT The global outbreak of SARS-CoV-2 has spurred a reassessment of Municipal Solid Waste management strategies and approaches. A significant need for sanitation and hygiene was accentuated for disease prevention and control with the onset of the pandemic. With an alteration of the status quo in waste management system, an unprecedented amount of face masks, protective equipment, and other biological wastes was generated in the form of Municipal Solid Waste . This upsurge of potentially infected wastes originated a risk of transmission amongst frontline workers. Furthermore, the potential contamination of Municipal Solid Waste was rendered as a legitimate threat due to improper collection practices, disposal and handling of solid waste. Several novel waste disposal techniques and waste management policies were also introduced during this period. However, the sanitation-policy making-occupational safety nexus remains inadequately explored under the prevalent COVID-19 scenario. Through the prism of shifting waste composition, this review offers a global assessment of existing solid waste management systems during the COVID-19 pandemic. The physiological and psychological hazards faced by the frontline workers were explored and instances of best-case and worst-case policies on solid waste handling were recorded. Modern methods of waste disposal and latest trends of policymaking were evaluated. A model study of unsupervised learning via Partition Around Medoids cluster analysis was undertaken to reveal underlying patterns of waste management policies. Although, the clusters were formed devoid of any socio-economic parameters, this study strives to indicate proof of concept and can serve as a precursor to advanced clustering studies. GRAPHICAL ABSTRACT


Introduction
The onset of a global trend for degrading environmental conditions has culminated in a mandate to revamp development policies worldwide.The pre-existing economic growth model is no longer viable with depleting levels of natural resources.With the adoption of a sustainable growth model, the preservation of public health and the environment became a top priority (1).
As a result, the importance of waste collection and safe disposal grew substantially.The provision for appropriate disposal and treatment techniques was critical for effective urban management and formulation of new policies.To this effect, the United Nations has declared waste-related services as key performance indicators of Sustainable Development Goals 11 and 12.However, the management of solid waste still poses a considerable challenge to the environment and impedes global green growth (2).Municipal Solid Waste (MSW) encompasses garbage originating in daily households, commercial sectors, and industries.According to recent findings, the volume of municipal solid waste is anticipated to surge to 2.3 billion tonnes by 2025 and 3.4 billion tonnes by 2050 (3).
Several countries have started re-evaluating their MSW management strategies in response to the SARS-CoV-2 viral pathogenic entity and consecutive worldwide COVID-19 pandemic (4).The onset of the pandemic outlined the significance of essential amenities in disease prevention, and controlfacilities involving sanitation and hygiene, adequate access to clean water, and effective waste disposal systems are paramount for mitigating the propagation of diseases.Hence, to prevent such transmissions, the demand for face masks increased dramatically -Yang et al. (5) reported a subsequent rise in the production of polypropylene (a key raw material) by 126% and cloth masks by 227%, respectively.Face masks have been observed to be effective in limiting the transmission of the COVID-19 pathogenic entities; nevertheless, improper handling of the contaminated masks and continued use of the same offer significant ecological and health hazards.According to Chowdhury et al., (6), 1,50,000-3,90,000 tonnes of plastic garbage would be generated due to the increase in the demand of facemasks.Such forms of wastes tend to form oceanic depositions owing to inefficient management.Furthermore, it raises sanitation workers' exposure to hazardous materials during waste processing (sorting, transportation, and recycling), which can negatively affect their health.As a result, effective disposal is critical to mitigating the negative impact of masks on human health and the environment.
According to WHO, proper waste management is one of the most essential practices that individuals can engage in, to restrict pathogenic transmission and avoid diseases.On the other end of the spectrum, the pandemic has also altered the workspace norms and culture of the employees.This resulted in a change in the systememployees were expected to perform their regular duties from the safety of their residences.It was observed that there was an increase in home delivery of food and supplies, resulting in increased demand for food packaging substrates and single-use plastic bags.During the outbreak, Parashar and Hait (7), reported that the usage of takeout services and online shopping also surged dramatically (China -50%, Singapore -65%, and United States -78%) (8).The COVID period witnessed a surge in global waste, which stressed the already burdened waste management system to a new level.Waste management services were already stretched thin by an escalating population, inefficient waste disposal practices, and a general lack of knowledge even before the pandemic.Apart from this, the induction of large-scale industrial setups has increased the amount of toxic and hazardous discharges added to the waste pile.All these factors have negatively impacted the waste handling scenario way before the introduction of the COVID-19 pandemic.Though, several techniques have been employed over the years, they have been found to be more detrimental to the environment.Moreover, open dumping of waste has resulted in soil and water contamination, along with seasonal issues such as clogged drains and sewage backflow during heavy rains (9).
Multiple measures have been implemented to manage solid waste from domestic, agricultural, and industrial sources.One of the most popular channels for MSW disposal has been landfills which have served as the primary method of large-scale waste disposal.Over the years, it has been observed that the practice leads to the generation of gases such as methanewhich results in increased greenhouse gas emissions, soil pollution and contamination of groundwater sources (10).Conversely, incineration is burning any form of waste at very high temperatures in the presence of oxygen (11).This waste disposal method is primarily regarded as a thermal degradation process and is classified under waste-to-energy processes.The incineration process was favored owing to its large feed capacityhowever, Datta et al., (12) reported that the fumes generated from the process were high in furans and dioxins and could harm human health and the environment.Moreover, the practice of incineration leads to the generation of oxides of nitrogen, carbon, and sulfur, along with toxic heavy metals and polyaromatic hydrocarbons, which are unsafe for inhalation (13).Subsequently, several instances of waste valorization studies were recorded as wellvaluable products such as adsorbents, electrodes, etc., were synthesized from refuse material.However, the operation of such specialized processes was also reported to be infeasible for large-scale implementation (14).
A subsequent review of the existing literature was performed on 20th September 2022 based on the Scopus™ databasethe search criteria used were 'article title, abstract, keywords'.The root search term opted for the search was 'COVID-19', and the total count of instances was recorded to be 3,65,079 publications.An auxiliary keyword, 'waste', was used to refine the prevalent search terms, and the total instance count was recorded as 2143.Figure 1 depicts a directed chord diagram for keywords used in the aforementioned publications.Each connection represents an article with two common keywordsto simplify the figure, we restricted the depiction of keywords to 5 or more common publications.Results suggest COVID-19 and SARS-CoV-2 are the most common keywords used, followed by wastewater, coronavirus, waste management and wastewater based epidemiology (WBE).
Thus, waste management systems were found to possess pre-existing flaws such as environmental degradation, complexity of process, capacity bottlenecking, high waste handling costs and lab-to-field transition.The onset of the pandemic progressively worsened the situation due to the generation of new forms of waste and an overall increase in the total waste generated.These changes in the status quo for solid waste management demand an in-depth analysis of the prevalent waste management scenario, especially for MSW.This study aims to adequately address the pre-existing dearth in literature for the case of MSW management (post-inception of the COVID-19 pandemic), and the following were reviewed: (iv) Case studies on solid waste management (Best and Worst case scenarios); and (v) Mathematical modelling based on the waste composition in different countries.

Change in waste composition
The waste generated in a community is a crucial metric, revealing the socio-economic inferences on the same.It indicates individual lifestyle, manufacturing patterns, and technological progress of the population.Since, there was a radical change in lifestyles and production trends, it is predictable that the waste composition will be altered over the last few decades (Figure 2).A trend was noted in the waste composition, with a gradual decline in organic waste and an increase in other types of garbage, with paper and metal waste showing the most significant growth, followed by plastic waste (Table 1).This tendency can be linked to the considerable shifts in consumer behavior and industry needs that have occurred during the past four decades (1980-2020).Unprecedented levels of instability in the social and economic systems globally have been caused by the advent of COVID-19.Every sector of society has been subjected to changemeasures of social distancing were implemented, and the public health system was   completely overhauled (15).High-income countries generated approximately 466 m 3 day −1 of (Hospital Waste water) HWW and 2-4 kg of BMW (Biomedical Waste) bed −1 day −1 and low-income countries produced around 95 m 3 day −1 of HWW and 4-6 kg of BMW bed −1 day −1 (16).Sanitary goods production and distribution during the pandemic were observed to follow an increasing trend, and a resultant stream of biological wastes was generated (17).The municipal waste composition has seen a significant amount of e-waste comprising discarded electronic appliances.The worldwide ewaste generation hit a record of 53.6 million tonnes in 2019, a 21% rise over the last five years (18).Furthermore, consumer behavior linked to the COVID-19 pandemic identified an adverse change in the waste composition.With the onset of the pandemic, the understanding of the viral entity and its associated significances was inadequate.Citizens panicked and made arrangements for food and household supplies in disproportionate amounts, in a failed effort to avoid the risk of shortages in the upcoming future.This trend of disproportionate consumption and instances of hoarding were prevalent around the world -84% of Norwegian respondents mentioned purchasing more dry products, 38% bought additional cans of food, and 37% acquired extra frozen meals due to panic of the pandemic, resulting in the burden of the waste management system by additional food wastage (19).The COVID phase also witnessed a surge in customer demand for online purchases and the frozen food sector.According to market research, Japan, Italy, and the USA were reported to be the highest consumers under the 'food takeout and delivery' category with an overall increase of 15-29%.UK and USA were also reported to exude the highest frozen food demand of 84.4% and 92.7% respectively compared to previous year (20).The expansion in online food sales and restaurant takeaway suggests the rise of plastic waste due to the continual growth of packaging materials.Moreover, Cariappa et al., (21) reported that lack of labor availability during the peak harvest time of wheat, paddy, barley, fruits, and vegetables, which overlapped with the COVID-19 induced confinement, resulted in massive food waste and financial damage for Indian farmers.Thus, inadequate scientific facilities for preserving the produce, consumer panic purchases, and online shopping aggravated food insecurity and wastage at the manufacturing, storage, transit, commerce, and consumption phases, ultimately changing waste composition internationally.
In recent years, the pandemic has altered the dynamics of MSW production, affecting sanitation workers and policymakers (22,23).This outbreak has caused a significant shift in the type of waste produceda rapidly increasing trend was observed in the quantity and volume of plastic waste used for single-use PPE, such as needles, respirators, gloves, and masks (24).Thus, the production rate of PPE increased massively during the COVID-19 period; for instance, in Iran, the production of face shields increased 1000 times (25).Similar trends were reported in the Kingdom of Bahrain, where waste generation was estimated to be 35,480 kg of face masks per day, 1,894 kg of PPEs per day, and 16,633,505 kg of syringe waste per day (26).Consequently, waste treatment facilities became overburdened, necessitating the engagement of emergency treatment and disposal methods (such as deep burial, cement kilns, industrial furnaces, and municipal solid waste incinerators).There is a risk of transmission due to such sub-optimal waste management procedures, resulting in the contamination of MSW by pathogenic entities (22).
Estimates suggest that there has been a significant rise in the quantity (3.4 kg person −1 day −1 ) of healthcare waste generated worldwide.Healthcare waste associated with COVID-19 was disposed at a rate of 2.5 kg person −1 day −1 in developing nations, with estimates of 2.0-2.2kg person −1 day −1 in Mexico, 2.23 kg person −1 day −1 in Indonesia and 2.85 kg person −1 day −1 in Thailand (27).The massive growth in PPE wastes was the primary contributor to the rise of healthcare waste in urban regions.Wuhan, China, witnessed an exponential growth of healthcare wastes from 50 tonnes (Jan 23) to 291 tonnes during its peak on 1 st March 2021 (5).Furthermore, healthcare wastes had reached 486.90 tonnes day −1 in all areas of China.India also witnessed an increase in healthcare waste generation (of almost 10%), amounting to over 600 metric tonnes day -1 .There is also a gradual increase in the complexity of managing plastic waste associated with healthcare waste.Our existing waste management system is insufficient and inefficient to deal with the growing use of plastic in such wastes, exacerbating its mishandling and leading to a new environmental crisis.Sharma et al. (24) further observed a prevalent trend in improper disposal of plastic based healthcare wastes to be a potential source of microplastic pollution.Microplastics derived from facemasks are hazardous upon inhalation by its users (28).It is evident the pandemic has increased the burden on managing solid waste worldwide, along with the challenges posed by the supply-chain bottlenecks in the production, demand-supply, consumption, and disposal of PPE.

Changes in waste handling practices
Proper management of MSW with altered composition poses a significant concern for policymakers to minimize human exposure to COVID-19 and environmental pollution (29).Separation was proposed based on the segregation of contaminated and non-contaminated healthcare wastes (30).According to the Medical Waste Control Act 380, monitored by the Environment Protection Agency of China, infectious wastes have been stored in yellow leak-proof plastic bags; MSWs were stored in fully-sealed black bags; needles were stored in plastic containers specially made to dispose of sharps; cytostatic drugs was stored in their original packing (31).After segregation, these healthcare wastes were stored in temporary storage sites, generally located inside the hospital.These storage spaces were created under rigorous guidelines, including requirements for sanitation, adequate ventilation, and easy access to water, among others.Only authorized disposal companies were allowed to transport healthcare wastes to the disposal sites.Pre-established routes were followed, and all their data, including site information, was collected.The destination disposal site and the transport trucks were also strictly monitored (32).A recent study reported that COVID-19 pathogens could survive on material surfaces for up to 9 days (33).To decontaminate such healthcare wastes stored in temporary storages, many guidelines were formulated, including socio-economic conditions and the technologies available in that specific environment.The main priority was incineration, which was the go-to method to dispose of all types of healthcare wastes, because it was the most apt method to destroy all traces of the virus.Microwave and steam disinfection were used in portable facilities created during COVID-19, where all the residuals were transported to secure governmentauthorized landfills.
During the pandemic, despite changes in people's lifestyles and the nature of municipal solid waste generated, the protocol for the management of MSW initially remained unchanged.On the other hand, the waste management system for PPE has improved under the new health guidelines, with a special emphasis on healthcare wastes.Prior to the pandemic, 70-75% of the municipal waste generated was recorded to be non-infectious and thus, the protocols for collection and disposal were simple.Firstly, the municipal wastes were collected in colour-coded bags and then stored in containers scheduled to be treated at local disposal plants.Cleaning of containers or the transportation truck was not followed as the wastes were non-infectious.Microwave disinfection, steam disinfection and incineration were used to treat them safely.The change in waste handling practices was perhaps driven by a shift of priorities amongst nation states.Since medical waste is extremely contagious, it was a major concern for authorities during COVID-19 to ensure the safety of frontline workers.

Health hazards faced by sanitation workers
There was a proportional increase in occupational risk faced by the municipal workers owing to the absence of appropriate safety measures required to undertake the task.Also, numerous bacteria and infectious microbes, such as thermo-tolerant coliform, E. coli, faecal coliform, Enterococci etc., thrive in hospital effluents and solid waste, making the workers vulnerable (34).A set of COVID curbing measures undertaken by various countries for frontline workers, is elucidated in Table 2.While in Solan, India, 63.64% of garbage collectors, 10% of waste pickers, and 79.5% of sweepers were equipped with safety equipment to handle municipal solid waste, in Mandi, India, it was reported that, 90% of workers suffered various forms of sprains and injuries (41).Furthermore, the incineration of MSW leads to the generation of toxic compounds such as dibenzo-p dioxin and polychlorinated dibenzofuran, which have been detected in fly ash.Emission of additives and PAEs were also detected in the ash residue, posing severe health hazards to municipal workers.Lu et al., (42) reported the collection and subsequent analysis of urine samples of workers in an MSW incineration plant in Shenzhen, China.The results depicted a higher concentration of mPAEs in the sample of plant workers than in the urine samples of residents living at 8 km from the plant.The study directly insinuates the presence of toxins in MSW and successively released during the incineration process.Rafiee et al. (43) conducted a similar study in the Aradkouh waste processing and disposal facility by collecting urine samples of 25 workers and 20 upwind residents.The results showed high levels of BTEX in composting workers' urine at the end of their shift, concluding they were exposed to high levels of BTEX.Apart from these, the chances of the biological hazard occurring are considerably higher, which resulted in communicable and waterborne diseases (44).
Generally, pathogens are transmitted by droplets, aerosols, direct contact, or from infected surfaces (Figure 3).Sommerstein et al., (45) revealed the deposition of particles less than 10 micronsthese particles were found to be respirable and can potentially reach the lower respiratory tract, whereas 10-100 microns of particles potentially remained in the upper respiratory tract.Smaller droplets evaporate rapidly and have little time to generate aerosols, whereas bigger droplets settle faster without evaporating and immediately contaminate the surrounding area.The pathogens lead to respiratory issues, low haemoglobin, and fewer RBCs and are incompetent outside the host but can tolerate extreme weather and consume host organic materials.Droplets and aerosols can be released when talking, coughing, inhaling, or sneezing and can fall onto surfaces, polluting them, or diffuse in the air and travel a distance.Aerosolized particles can also bind with air contaminants and disperse further.This endangers healthcare facility cleaners and garbage collectors and can be a source of contamination (46).
Earlier studies showed that, on average, the face masks used daily by the urban population is expected to cross the 7 billion mark.The exponential increase in the generation of medical waste was recorded by Chowdhury et al. (47) -HCW was reported to be 658.08 tons in March of 2020 which increased to 16,164.74tons in April of 2021.It has also been noted that globally, Asia accounts for 54% of the daily face mask consumption, which in turn not only increased the workload but also increased the rate of contamination.The spread of the virus depends on its lifespan on various surfaces, as prolonged exposure to such infected surfaces might increase the risk of infection (35).It has been demonstrated that the virus can Table 2. Covid curbing measures undertaken by various countries for frontline workers.

Country
Steps taken to curb Covid-19 among frontline workers References Austria -Reduction and isolation of waste to limit virus transmission, especially in municipal waste systems.-During the early phases of the outbreak, residents were instructed to restrict and separate their garbage Oza et al. (37) Belgium -The government instructed the populace to dispose of their waste regularly to prevent mass deposition -Instructed to properly seal the garbage bags before discarding them

Brazil
-Used PPE and facemasks from residences be stored in separate bags instead of being collected with regular garbage.-Frontline workers use double bags to contain potentially contaminated waste.
-Frontline workers are provided with sanitizers and instructed to sanitize vehicles and equipment before and after each shift.-To prevent infection, the government replaced its elderly and ailing workers.

China
-Infectious healthcare waste should be managed in accordance with medical waste standards.
-Collection and disposal of infectious medical waste should be prioritised by the medical waste disposal unit.-Incineration of hazardous wastes should be done in accordance with the competence of the health authority

Sharma et al. (24)
India -Waste from COVID-19 isolation wards will be handled using two layers of protection.
-Trash bags should be labelled COVID-19 so that the Common Bio-medical Waste Treatment Facility (CBWTF) can provide priority disposal treatment.-Separate workers were deputed for medical and general waste management.
-For timely waste collection, CBWTF should be informed about homecare and quarantine facilities.-Frontline workers should be equipped with PPE kits and sanitization should be performed on a consistent basis.

Sharma et al. (24), Kulkarni and Anantharama (35)
Italy -Two main categories are made for waste collection: TI -Houses with positive COVID-19 patients and T2 -Houses without positive COVID-19 patients.-T1 wastes are infectious medical wastes that must be managed in accordance with the legislation.They must collect in bags with two layers -T2 wastes are managed using a collecting system designed specifically for them, in which they are gathered in two sealed bags.-Frontline workers should wear PPE equipment.

Lebanon
-To follow new legislation and predefined garbage collection, sorting, treatment, and disposal procedures -Instructions for frequently sterilising equipment and vehicles using disinfectants -Instructed to use PPE to prevent exposure to the virus.

Netherlands
-Reduce the volume of waste collected and the duration of garbage collection work.
-Residents were instructed to retain dry garbage like textiles and newspapers for as long as they can before bringing them to a recycling facility.-Introduced an underground storage system with an automatic mechanical arm to transport the containers.

Salvaraji et al. (39)
New Zealand -Provided frontline workers with PPEs to maintain their safety and avoid infection.
-Contaminated garbage from households, such as face masks and PPE, must be recycled as regular waste

Das et al. (4)
United States of America -Workers who collected infectious garbage were not required to take any further precautions beyond those necessary for managing solid and liquid waste.-COVID-19-contaminated solid waste must be managed using safe work procedures and personal protective equipment.-Social distancing between frontline workers and sanitary precautions should be taken for vehicles, equipment, and workers.survive on the surfaces of inanimate objects; therefore, caution must be exercised while handling items that have been in contact with an infected individual.While food and its packaging have not been found as a significant factor in the spread of the disease, the virus's ability to persist on surfaces for several days can lead to contamination and spread.Food-related objects used by infected patients, such as wrappers, plates, etc., can be a source of contamination if they encounter waste management staff, which could result in the spread of the virus (48).Confined places are hotspots for contamination and cause COVID-19 surges.The spread of this virus from an infected individual to others in a confined environment was modelled using aeroplanes, vehicles, and hospital wards.If conditions are favorable for the virus and necessary precautions are not taken, an infected person or corpse in a hospital could be a source of infection.This could endanger waste management workers during transit and collection (46).
The contaminated waste must be burned at high temperatures to kill viruses.It is impossible to separate wastes based on virus particles; therefore, recycling the MSW poses a danger of spreading the virus, thereby leading to an increased collection of non-recyclable garbage.In poorer nations, MSW is usually buried or burned.The former causes viruses to seep into the soil, where they may resurface and trigger additional viral transmissions.Therefore, investigating soil-pathogen interaction is necessary.Open burning of MSW, primarily plastic, can spread infections, raise GHG emissions, and produce toxic chemical compounds, including furans and dioxins (49).
Since the inception of the pandemic, there has been an increase in the occupational health hazard among frontline workers resulting in an increasing scare among the workers for their lives.Along with this, the public has been stigmatized by the occupation undertaken by frontline workers and corporations, which has led to a further increase in scare concerning the transmission of the virus.

Stigma concerning sanitation workers
The COVID-19 pandemic drastically affected the solid waste management scenario in countries around the globe, with countries finding it difficult to handle the large amounts of bio-medical waste being generated daily.This has increased pressure on the existing facilities and establishments and has impacted workers' lives in the solid waste sector.Workers such as the garbage collectors associated with the municipal corporations, unorganized rag-pickers, cleaners, and workers associated with the MSW separation units are at a higher risk, as compared to the general populace, due to their constant exposure to the contaminated waste (50).Alomari et al. (51) conducted a survey-based study on people's attitudes towards contagious waste management.They observed that a large section of society considered proper handling of the contaminated waste a collective responsibility and displayed a positive approach.However, the practices of throwing contaminated waste in the open environment, lack of segregation and know-how in waste handling still exist.Such practice has added to the already existing burden on sanitary workers, which not only affects them physically but also impacts their psychological wellbeing.Kaba and Akin Sari, (52) reported that there had been an increase in the cases of insomnia, stress disorders and phobia after the onset of the pandemic, along with other mental health disorders, highlighting the psychological impact of the pandemic.A study conducted by Haque et al. (53) on informal waste workers in Bangladesh revealed that around 81% of the workers faced psychological distress during the pandemic period, with issues such as depression, social dysfunction, and anxiety along with a constant fear of spreading the infection to their family members as well as losing the source of livelihood if the virus contacts them.
As discussed, sanitary workers face several social prejudices that harm their mental well-being (54).The pandemic has introduced a new dimension of fear, which has further contributed to the psychological burden upon sanitary workers.Their constant contact with contaminated waste, lack of proper personal protective equipment, lack of personal hygiene, inaccessible medical facilities and improper waste disposal practices have developed a fear towards the frontline sanitary workers.There has been a reluctance to work and a loss of motivation among frontline workers, especially the waste sector employees, mainly owing to the phobia of getting infected as well as due to the burden of social isolation faced by them (55).Labelling sanitary workers as active pathogen carriers has given rise to several psychological complexities, which significantly hampered their mental well-being.

Downfall of solid waste management system
Ganguly and Chakraborty (56) recorded the first cases of COVID-19 in India by late January 2020.In 2021, India recorded up to 10.6 million SARS-CoV-2 cases, with Brazil falling behind at 8.57 million.With an increased burden of MSW and poor handling and disposal systems, third-world countries have been thrust kneedeep into a mess of highly contagious and infectious waste materials.The following case studies present a deeper insight into the poor condition of the MSW management system, impacted by the onset of a deadly global pandemic.

Waste management challenges, India
The advent of the COVID-19 pandemic diminished the budding culture of effective recycling of MSW in India.Innovations aimed to facilitate the transition to a circular and green economy were largely undermined with the onset of the pandemic.Furthermore, the risk of potential contamination thereby renders the previously valuable portion of MSW useless.Moreover, the sudden nationwide lockdown coincided with the peak of the harvest season for summer crops.This led to large amounts of food waste, contributing to MSW accumulation.Polymers like polyethene, PET, polypropylene and PVC formed a considerable portion of the solid waste during the pandemic.This was primarily accredited to the abrupt upsurge in consumption and shipping.Packing and recreational amenities utilize copious amounts of polymer-based plastic packaging, resulting in a subsequent increase in plastic waste.As mentioned earlier, PPE kits, gloves and masks are made up of polymers.Accelerated usage of disposable protective gear was also observed in homes, offices, and hospitals.Incineration at temperatures exceeding 1100°C (56) has been the conventional method with the most optimum efficiency for handling such polymers, however with its volume increased manifold during the pandemic, copious amounts of harmful, toxic, and carcinogenic dioxin and furan fumes were being released into the environment.These gases negatively impact the immune and endocrine systems by bioaccumulation in adipose tissues (56,57).These deadly consequences can be avoided by replacing gas pre-treatment facilities with incinerators.However, there is insufficient provision of these amenities, with mere 198 biomedical waste treatment centers nationwide, thus reflecting the weak treatment infrastructure (58).
From June to December 2020, the pandemic generated 146 tonnes of COVID-19-related municipal solid waste per day in India (59) due to cotton swabs, syringes, empty isopropyl vials, and PPE kits.COVID-19 virus remains active and living on inanimate surfaces for nine days (36); hence, any MSW collected prior to treatment should have been left untreated for nine days.As a result of lax regulation and misunderstanding on the part of waste workers, the pre-COVID obligation of 72 hours of storage prior to sorting was maintained, resulting in several preventable infections.Due to irresponsible and disorganized segregation of contaminated and uncontaminated wastes from home and industrial sources, municipal sanitation employees and rag-pickers were subjected to long durations of exposure while physically segregating and sorting MSW.Long-term waste exposure, primitive equipment, lack of training, and inadequate safety procedures increased the susceptibility of workers to COVID-19 (60).By March 2020, 20% of Mumbai's sanitation workers had contracted COVID-19 due to bad protocol execution, lack of insurance, and other socioeconomic factors (61).
With the relaxation in the precautionary measures during the lockdown, Delhi was predicted to have a marginal surge in the number of positive cases by 17 th May 2020.The massive challenges to tackling the spread of the infection were lockdown protocol violation, poor funding of health care, deficiency in facilities for quarantine, inadequate testing labs, etc.In a densely populated country like India, the requirement of frontline workers was more, and training of the volunteers was required.The paramount and the follow-up for the long-term were becoming necessary with a collaborative effort.The inefficacy of the prevalent waste management system coupled with a slow rate of policy modernization adversely affected the situation for India.Furthermore, a high population density and the saturation of healthcare institutions progressively worsened the situation.

An unsustainable setback, Brazil
Brazil's solid waste management paradigm coincided with that of India.Preceding the onset of the COVID-19 pandemic, 30% of the collected waste in Brazil and 13% of the nation's MSW was profitably recycled (62).During the pandemic, a considerable growth rate of 28% was observed in the generation of solid recyclable waste such as glass, cardboard, paper, plastics, etc.This was primarily attributed to the increase in the usage of single-use plastics and the disposal of plastic, paper or cardboard packaging from shipping and courier deliveries of food and other items purchased online.The manual sanitation workers regularly encountered recyclable materials, which directly contributed to the increase in the positivity rate.Like in most developing countries, the provision of proper personal protective equipment to Brazilian workers was reported to be sparse and irregular.Furthermore, plastic, paper, and cardboard comprised 64.6% of the recyclables in Brazilian recycling programs.The bulk of recycling centers in Brazil was focused on manual garbage screening; workers were at a higher risk of getting infected.Thus, recycling programs in the country were suspended under the recommendation of the Brazilian Association for Environmental and Sanitary Engineering (63).Following this, 14 out of 30 major cities in Brazil stopped their recycling programs.As a result, a lot of salvageable resources were wastedit was estimated that recyclables worth USD 781,000 were disposed of into landfills, occupying 19,000 m 3 in volume (64).This resulted in a subsequent reduction in the landfills' lifespan and economic and environmental loss.
The medical waste generated in Brazil was calculated to be significantly less than the existing capacity of the prevalent waste management systems.Before COVID-19, 2,52,948 tonnes were being generated per annum, accounting for only 63.8% of the total capacity of systems in place (65).Recent data shows that more than 35% of Brazil's medical waste is not treated suitably (64).Brazil's medical waste treatment infrastructure has been predicted to saturate, and its amenities were estimated to exhaust with the doubling of the standard medical waste output.The threat of resource exhaustion was reported to be tangible by drawing parallels to the situation in Wuhan, which experienced an exponential six-fold increase in its medical waste output as an immediate response to the COVID-19 outbreak.The Brazilian waste sector formally employed 82,213 workers in the year 2020.Until April 2020, 178 positive cases were reported among the workers, 13 of whom died, representing a mortality rate of 5.8 per 1,00,000 inhabitants (66).It was observed that the positivity rate was 5.5 times higher in waste workers compared to the rest of the population (63).As for the formal and informal waste workers, a severe lack of ample training on the appropriate use of PPEs and COVID-hazard-free working environment in MSW sorting units was recorded.These factors left the workers vulnerable to contracting COVID-19 from the possibly infected MSW materials.Instances of exploitation of waste workers under the employment of cooperatives were also recorded.Such workers were deprived of access to emergency financial support for COVID-19 from the municipality.Hence, they had to risk infection and work under horrid and deadly conditions to secure a minimum livelihood.

Containment failures, China
In Wuhan, China, the first case of COVID-19 worldwide was recorded in December 2019.The Chinese authorities quickly employed measures to facilitate the containment of the viral pandemic.However, several data censorship and misinterpretation of the outbreak were recorded (67).The sudden increase in waste resulted in significant problems with waste disposal since it exceeded the disposing capacity of the pre-existing facilities.Aside from applying proper disposal methods, the disposal rate was also pivotal in mitigating the contamination of viral pathogenic entities.Hence, cities in China underwent a series of changes in their waste management techniques and routines (28).Authorities were instructed to establish separate garbage bins for used masks.Municipal waste was collected and treated as a contaminant to mitigate pathogenic transmission.New waste collection norms resulted in a dearth of human resourcesthe vehicles assigned for collecting special wastes and MSW needed to be regularly sanitized.This inculcated a significant rise in human labor and costs over time.China had a relatively lower mortality rate, for being between 1% and 3%, but it always stood the chance of an upcoming wave hitting upfront (68).Though, China's on-site treatment methodology to limit waste was highly appealing, there was no reported data to what extent it affected the environment.Despite failing to serve good policies for stopping contamination, China has excelled in providing stringent COVID waste management procedures.Parallelly, the technological improvements brought to the sector of MSW management during the COVID era proved to be highly resourceful.

Shortcomings of waste management in Italy
Italy was one of the first countries outside China to be seriously affected by COVID-19.It recorded its first positive case, two Chinese tourists on 29 th January 2020, and its first indigenous case, a 38-year-old Italian man on 21 st February 2020 in Codogno.Within four weeks, Italy witnessed 75,528 positive cases and 11,591 deaths, forcing the country into a nationwide lockdown (69), which was months after cases of COVID-19 were reported in Italy; this time, many workers could have been exposed to the virus.Most of the cases were recorded in Northern Italian regions like Lombardy, Emilia-Romagna, and Veneto, which accounted for 46%, 13% and 9% of the country's total cases, respectively (70).Due to COVID-19, the complete MSW collection, handling, and disposal system had to be changed.Although the amount of waste generated during the lockdown had reduced considerably, the amount of contaminated and hazardous waste had increased, which required modifications in the protocol for handling the waste to protect the workers from being infected (71).Given the emergency and the lack of experience in dealing with the virus, it was unavoidable that some strategic mistakes were made.Delays in the publication of new protocols regarding the management and collection of waste impacted the safety of the workers.The risk of contracting the virus is higher in curb-side collection systems since the workers touch metal, paper, and plastic surfaces on which the virus can survive.However, no modifications were made to the existing collection system to protect the workers.
According to the guidelines published by the Italian Health Institute, based on the technical report from the European Centre for Disease Control (72), waste from infected patients needs to be marked as Residual MSW to simplify the disposal procedure.The waste must be double-bagged, and the local health district must be informed to initiate a unique collection protocol (71).However, these protocols were published late and lacked details.One major flaw in the new guidelines was that the citizens were not advised to store the waste in the house for virus inactivation before disposing.Italy also did not impose a minimum storage time for the waste before being transported to the landfill or incinerator.A minimum storage time of 72 h reduces the risk during waste handling and transportation (73).Another contributing factor that affected the workers' safety was waste collected from asymptomatic and untested patients.Since the waste generated was not separated or marked as residual MSW, the contaminated waste matter was reported to encounter other wastes collected and facilitated the transport of viral matter.The delays in policy formulation and implementation were the primary deterrent factor for Italy.Moreover, the apparent trend of negligence in worker's safety and improper waste disposal directives further intensified the issues in solid waste management.

Evolution of efficient solid waste management during COVID-19
4.1.A flexible approach, South Korea South Korea was one of the most affected countries in the beginning, and the number of cases remained high until 2 nd March 2020, after which there was a significant reduction, and the situation began to stabilize on 14 th April 2020 (74).On 28 th January, the Ministry of the Environment issued the first edition of unique procedures to be followed for properly handling COVID wastes following the first confirmed case (75).The Ministry of Health and Welfare has released new instructions that no COVID wastes can be retained for more than 24 h, that the responsible authority must give it a top priority, and that wastes from self-quarantined households must be treated as COVID waste (76).The Korean government decreed that asymptomatic people cannot dispose of their waste outside their homes until they have been confirmed to be COVID-negative, after which such waste will be treated as regular waste along with MSW.Meanwhile, waste generated by selfquarantined households was double packed in dedicated plastic bags or synthetic resin containers, depending on the severity of the virus, and then transported to a local public health care center, where it was burned in an incinerator.
According to the Ministry of Environment (South Korea), the country generated 295 tonnes of COVIDrelated trash from early February to early March 2020, with roughly 18% of the garbage coming from self-isolated patients; however, by the mid-July, more 2,600 tonnes of medical wastes were generated from 91 COVID-hospitals, 8 residential centers, 24 temporary facilities and self-isolated households being disposed on a priority basis (75).The exceptionally high detection rate was discovered to be the fundamental factor in South Korea's effectiveness in suppressing COVID (74).Another thing that may have aided them is their remarkable literacy rate of 97% and a national awareness program for trash management generated by self-isolated homes.However, South Korea did not recover completely from COVID as quickly as China since Korea experienced a late boom in COVID active cases in the third and fourth quarters of 2020.A prepared waste management model can aid both calm and crisis, and recovers well (77).Inappropriate COVID waste management is not optimal, and the study emphasizes the need of waste management.South Korea took more flexible and targeted measures to reduce COVID waste, and the organized and prioritized cooperation across government departments undoubtedly assisted them in dealing with the matter far more effectively than some of their counterparts.

A swift recovery, Malaysia
Malaysia announced its first COVID-19 case on 25 th January 2020.It witnessed an exponential surge in cases while the country went through the transformational constitutional era due to a large gathering of Islamic missionaries in Sri Petaling (27 th February 2020) (78,79).Due to their tendency to socialize and the fact that social meetings are an integral part of daily life for Malaysians, it was difficult for them to comply with the stringent regulations during the early stages of movement control order (MCO).Furthermore, the pandemic's unemployment and apprehension about the future severely impacted people's psychological well-being (80).
From 18 th March to 3 rd May 2020, the Malaysian government adopted the MCO because of the high increase of COVID-19 instances occurring since 14 th March 2020.Fortunately, on 29 th April 2020, the MCO effectively broke the chain of COVID-19 infection in Malaysia with the lowest daily cases figure (two-digit number) reported since the MCO's implementation.The recovery rate was also 68.91% (78).During the pandemic, the Malaysian state brought social distance SOPs into placeindividuals must keep a minimum of one meter between each other to reduce the danger of infection, businesses and retail establishments should mark the ground with a 1 m to indicate the line length for consumers, The Ministry of Health promotes no-handshake policies in the workplace and upholds a one-meter physical separation between employees (81).The increasing population and rapid urbanization in Malaysia directly influenced the MSW generation, which had an exponential rise from 5.6 million tonnes in 1997 to more than 8 million tonnes in 2010, with a projection of more than 9 million tonnes by 2020 (82).Consequently, the government emphasized the co-efficiency of the MSW treatment scenario as it is essential to be conducted particularly associated with national policies with a target to reduce the burden of contaminated waste and achieve the Sustainable Development Goals according to the local condition and necessities (83).

Success from analytical approaches, Taiwan
With the onset of the first phase of the pandemic, the widespread use of non-pharmaceutical measures had a decisive role in regulating the transmission of pathogens.The considerable economic and social costs were associated with maintaining travel bans and metrics of physical separation, which indicate that these control methods may not be viable and that policymakers must seek alternatives to alleviate the constraints (84).Taiwan was among the few nations to pioneer progress in eradicating the pandemic without imposing stringent lockdowns or school closures.While the country was formerly regarded as a COVID-19-prone breakout region primarily because of its close economic and geographical relationship with China.Conversely, six months after the outbreak, Taiwan possesses one of the world's lowest per capita incidence and fatality rates of COVID-19, without any local diagnosed cases between early April and mid-August.Taiwan employed the 'containment-as-mitigation' or elimination method earlier to avoid overburdening the healthcare system.Border control, case-based treatments aimed at COVID-19 patients, and population-based measures geared towards the public were all part of this strategy.Casebased remedies comprised case identification and seclusion using sensitive monitoring systems, contact tracking of patients diagnosed to identify secondary infections within tight social circles, and 14 d quarantine of close contacts (regardless of symptoms).Face mask usage, personal cleanliness, and physical distance were among the population-based measures (primarily voluntary) (85).
All the waste produced by the healthcare institutions was processed in incinerator facilities that have received government certification.Considering that medical waste and municipal garbage may be intermingled, the operating temperature of municipal waste incineration facilities was appropriately raised to destroy viruses efficiently (86).Despite Taiwan's recent success, it indeed unclear which of the following vital programs played a substantial role in containment.A detailed comprehension of intervention efficacy would aid in preparation for the forthcoming wave and support phased countermeasures, particularly during the reopening.This post-hoc assessment is incredibly significant since solid border control and severe physical isolation have immediate and long-term socioeconomic consequences.Several simulations investigated the performance of case-based and community treatments.However, their preponderance concentrated on 'whatif' assessments by modelling counterfactuals without inductive connection to real-world settings and source data (87).

Ideal policy implementation, Macao
Macao, with its inherent efficiency, was able to locate, control, and eliminate COVID-19 throughout the country.It sheds significant insight on the provision of healthcare, public safety, inter-communal cohesion, and municipal administration.By mid-July 2020, COVID-19 was eradicated, and Macao was successful in restoring stability and the country's appropriate regulations resulted in a low city-population vaccination rate (88).The effectiveness of Macao's COVID-19 strategy and the ongoing vaccination campaign also emphasizes the rising imbalance and inequality in vaccine production, availability, and accessibility, coupled with a judicious and timely roll-out schedule (89).
On 9 th February, a three-phase complimentary vaccination procedure was commenced, including an easyto-use mobile online booking platform along with several vaccination centers.Since Macao's immunization objectives are comparable to those of other low-risk provinces, the elderly was reportedly exempted.Phase 1 involved frontline employees, educators, and those involved in the metro's commercially significant casino and tourist industries.To identify and limit the spread of COVID-19 in the community, the Macao authorities implemented a 'closed loop' system.The authorities have assessed potential changes in the COVID-19 scenario might affect reopening reactions with recommendations like residents and non-resident employees stay in the territory for the Chinese New Year in February 2021 after 400 COVID-19 cases were detected in Hebei and additional isolated cases were recorded elsewhere in China (90).
COVID-19 NAAT testing, health code app, hotel quarantining, mandatory masking policies interventions and containment efforts have been publicly recorded for over a year.The city's administrative and political state has achieved respect for its capacity to react quickly to implement these policies in combination with COVID-19 control mechanisms.According to statistics, most Macao individuals are content and appreciative of how the outbreak is being handled, and information is being disseminated.However, the result has been lowered risk perceptions and, as a result, a low vaccination rate (91).The absence of an efficient MSW sorting and recycling infrastructure impeded Macao's containment efforts.Incoherent knowledge on MSW handling and a failure to source separate wet and dry wastes also posed serious challenges to the nation's efforts in eradicating COVID-19.To address such deficiencies, the economics of MSW, and the nexus of society were developed by boosting local recycling businesses and standardizing recycled goods and recyclable materials.Furthermore, the city uses technologydriven waste solutions to meet challenging policy objectives, such as a 35% recycling rate for produced garbage by 2030 (92).
Macao's economy relies heavily on tourism, and the constant opening of bordersthe travel bubblehas assured some visitors.It was however, limited, and more is required to put the sector into profit.A vaccinated population, many frontline employees, would boost visitor assurance, reliability, and safety.With vaccinations being rolled out throughout Asia and borders reopened, Macao is still a critical case study of lessons learned (93).

Post COVID-19 measures concerning solid waste management
Post hoc analysis of the solid waste composition after COVID depicted a disproportionate increase in the biomedical waste fraction present in MSW.Such wastes primarily consisted of discarded facemasks and different forms of used PPEs.While there are well-defined methods to handle MSW, the same methods of disposal cannot be extended to such new forms of waste.healthcare wastes were mandated to be segregated and disinfected on a large scale to restrict biohazards and pathogenic contaminants.Hence, direct reuse of facemasks and other PPEs or, valorization of healthcare wastes gained precedence during this period.

Overview of disinfection technologies
During COVID -19 healthcare workers and frontline workers were recommended to exercise the use of N95 masks.These N95 masks are single-use and disposable.With a drastically increased demand for masks and limited supply, there is a need to find a proper and effective technology to disinfect the contaminated masks and reuse them, as they add the existing pile of MSW.Before the pandemic, the surgical masks used were disinfected by treating with ethanol, hydrogen peroxide, bleach, UV -C light and other techniques (94).Nevertheless, with the onset of the pandemic, there was an urgency to explore other techniques available to disinfect the masks and improve the efficiency of the existing processes.The following section discusses techniques to disinfect the healthcare wastes found in MSW.
Ozone treatment: It has been widespread for various applications, which include water treatment, air purification, food processing, etc. (95).Continuous positive airway pressure development employs ozone to carry out this disinfection process, with factors such as concentration, time, and humidity affecting the systems effectiveness.It was observed that when the relative humidity was below 50%, ozone proved to be a reasonably poor disinfectant.However, as the relative humidity was increased to 80% or more, the efficacy of the process improved exponentially (96).In the case of municipal solid waste, ozone treatment is particularly successful because the composition's relative humidity is 60% or higher.An investigation performed at Nara Medical University, Japan in 2020 demonstrated the efficacy of ozone treatment for cleaning by sterilizing a piece of stainless steel at a relative humidity of 60-80%.It is also observed that ozone treatment has very little or negligible impact on the filtration efficiency of the material of the face mask, which forms a considerable portion of the MSW after COVID (97).
Autoclave treatment: This method is employed for sterilizing medical devices by heating at a higher temperature, which eliminates the bacteria in the device.The required temperature is obtained in the form of steam, which can remove all the microorganisms on the health care wastes, present in MSW The sterilization is carried out for 34 min, heating at an atmospheric temperature of 121°C, and then a drying time of 5 min.However, it should be noted that high temperatures and pressure may damage the PPEs, thereby reducing the article's lifetime (98,99).
Ultraviolet treatment: Ultraviolet-C treatment is one of the disinfection technologies that can damage the RNA and DNA of the virus, thereby aiding in the decontamination of the face masks, present in considerable portions within the MSW.A parallel beam of light having a wavelength of 245 nm is emitted on a box reactor at a low pressure equipped with ultraviolet lamps for disinfection (94).The entire process must be carried out 16 times to ensure that the UV-C light can penetrate the pathogen cells and damage the virus's RNA.MS2, Phi6, bacteriophages and Methicillin-resistant Staphylococcus aureus (MRSA) were the test strains for testing the efficiency of UV -C light against viruses on masks.The elimination of bacteriophages was always less than MRSA, whereas the elimination of Phi6 and MS2 virus was almost similar for most tests.It was observed that the decontamination of viruses was lower in the N95 face mask as compared to other PPEs, with the inner layer of the mask being able to retain a higher amount of virus as compared to the outer layer due to the permeation of the suspended liquid (100).
Dry heating: The application of dry heating technology at 70°C kills 7 different types of bacteria and enables the inactivation of the H1N1 virus.The H1N1 virus, resembling SARS-CoV-2, is an RNA-enveloped virus that spreads via the respiratory system.Therefore, the H1N1 virus can be used to assess the effect of decontamination of various forms of PPEs present in the MSW, via dry heating (101).Though, the National Health Commission of the People's Republic of China advised carrying out dry heating at 56°C for 45 min to decontaminate the N95 mask, Xiang et al. (101), recommended a minimum temperature of 60-70°C with a residence time of 1 h for maintaining the filtering efficiency.Another dry heating approach was Microwave-generated steam is used to treat MSW contaminated with COVID affected health care wastes, such as face masks.It was observed that the disinfection rate was very rapid as compared to the disinfection rate of dry heating.The N95 masks, were disinfected within 90 sec when operated at 1800 W without any reduction in the filtration efficiency, thereby making the process of microwave-generated steam drying quick and effective (102).

Policy changes implemented
National and worldwide waste treatment and management regulations and reforms proliferated during the COVID-19 era in response to the massive amounts of waste.The infectious nature of the garbage and its sheer volume compelled governments worldwide to devise innovative strategies for segregating, disinfecting, transporting, and disposing of hazardous waste.The World Health Organization (WHO) has issued recommendations on how to treat various types of garbage, including infectious waste.Per the guidelines, a leak-proof, durable plastic bag in a container (autoclavable waste bags in case of highly infectious material) should be used to store such wastes.The bags should be yellow with a biohazard symbol, and the collection frequency should be at least once a day or when 75% of the bin is full (103).The guidelines already existed on paper, but the COVID-19 era marked their tation, with each nation developing its policy depending on its economic capacity and technological advancement.
To combat the growing influence of the pandemic on the existing waste-handling infrastructure in Afghanistan, the Ministry of Public Health enacted two special provisions: the Stakeholder Engagement Plan, which was implemented in March 2020, and the Environmental and Social Commitment Plan, which was enacted during the same period.In addition to the conventional method, a stringent protocol was implemented to ensure the proper separation, transportation, and storage of waste from various residential and commercial sources.The healthcare facility's waste was segregated at the point of generation to separate noninfected waste from infectious waste and then stored it in specially designated areas.Before the waste was delivered to the treatment and disposal sites, it was labelled correctly to avoid spreading the virus (104).
China was one of the first nations to report cases of COVID-19 infection, and immediate action was undertaken to guarantee the correct disposal of the contaminated waste.The Ministry of Ecology and Environment has disseminated official notices for COVID-19 waste management (January 2020), work plans for waste management in medical institutions (January and February 2020), and guidelines for the management and emergency treatment of infectious waste in medical institutions (January 2020) (105).In India, the Biomedical Waste Handling Rule, 2016 has already been implemented to ensure the proper management of biohazardous waste.After the pandemic outbreak, the government issued new guidelines and regulations to limit the spread of infection through waste management systems.The Central Pollution Control Board of India (CPCB) established guidelines that provided insight into the treatment, handling, and correct disposal of waste created throughout the various steps of COVID-19 treatment.In addition, several regions' State Pollution Control Boards established fundamental recommendations to prevent further damage from the current pandemic.Different carts and bins were developed to collect garbage from wards housing COVID-19 patients in medical facilities, and the waste was placed in yellow bags labelled 'COVID-19 Waste' to prevent cross-contamination.Solution of 1% sodium hypochlorite was used to sanitize the bins and carts, and GPSenabled tracking of waste-carrying vehicles was implemented to ensure appropriate disposal (106).
Ministry of Health Kenya tabled two recommendations, namely the 'Interim Infection Prevention and Control Recommendations for Coronavirus Disease 2019 (COVID-19) in Health Care Settings' and the 'Safe Management and Disposal of Safety Product in Prevention of Spread of COVID-19' to tackle the infectious waste generated during the pandemic.According to the recommendations, all the infectious waste had to be placed in yellow-coloured bins marked as 'Danger/ Hazardous/ Medical' It was advised that the waste workers should avoid sorting through the waste contaminated with the virus and reusing should only be done after meticulous disinfection of the articles have been performed.All the bags should be sealed off and collected in the designated areas, with restricted access after being filled up to the 67% mark (107).
After the commencement of the pandemic, the Sri Lankan government released a letter (letter number: PL/7/1/18/1) outlining the guidelines for managing solid waste generated from both household and selfquarantine sites.The facilities responsible for the care of quarantined patients were instructed to collect all waste in yellow-coloured high-density polyethene bags with thicknesses not less than 25 microns or low-density polyethene bags with a greater density than 55 microns.The bags must be sealed and placed inside a second yellow bag to prevent spilling and leaking.The bags were recommended to be collected every third day after storage and adequately sanitized before being loaded onto the vehicle.To prevent the spread of infection due to the gathered waste, the agencies were instructed to dispose of it via incineration (108).
In response to the escalating transmission of the COVID-19 virus, South Africa has established a national plan for creating strategies and implementation pathways in the field of public hygiene.According to the plan, only a minimal amount of hazardous waste should be held at the source sites.Once the bins reached three-quarters capacity, they were to be sealed and transported to a central storage facility before further treatment.At the storage facilities, signs were put up to alert people about the existence of COVID-19-contaminated garbage.The locations should only be accessible to authorized people, and storage should take place in plastic bags with a minimum capacity of 60 L and a minimum thickness of 80 microns.To reduce the associated health concerns, there should be a maximum delay of 72 h between the collection and disposal of trash (109).Hence, the policies adopted by various countries were crucial to restricting contamination through inefficient channels of solid waste management systems.A prevalent trend was also observed regarding a country's waste management policies and average waste composition.

Mathematical modelling
Using UNSD's 'Composition of Municipal Waste' from February 2020, a mathematical model was developed for this study.(Table 3).Country (ISD codes) as well as percentages of plastic, glass, metal, textiles, and other inorganic waste were imported into R x64 4.1.2.Using UN waste composition statistics, the countries were shown on a 2D scatter plot for clustering visualization.PCA was used to reduce the dataset to two dimensions.Incompliant data values were omitted from comparisons.By waste composition, nations were clustered using an unsupervised K-means algorithm.The 'Silhouette' method was utilized to ascertain the ideal number of clusters (Figure 4).The PAM technique created clusters using the optimal cluster count of 2. PAM was preferred over K-means owing to its sensitivity to outliers.The plot was visualized using the 'fviz cluster' function of the 'factoextra' library.The application generated circular graphs with boundary clusters.Figure 5 depicts the clusters of the dataset as points connected to medoids through the 'star.plot'feature.Supplementary 1 compares the waste content of each cluster's exports.Based on clustering data, the policies of similar countries should have similar outcomes.A country from each cluster was compared side-by-side in light of the premise.Comparing waste composition and management policies allowed for the identification of patterns.Group 1: Armenia -Georgia; Group 2: China -Singapore; Group 3: Argentina -Panama (Table 4).These groups were formed as example comparison sets and the group were chosen on the basis of an uniform distance from the medoid.
Armenia -Georgia (Group 1): In Armenia, solid waste is usually managed through the act of landfilling.As per the Unified website for the publication of the draft legal acts of Armenia, in 2019, there were 339 landfills operational in Armenia covering an area of 494 hectares (110).According to the reports presented by the government of Armenia in 2020, excess of fifty sub-legislative acts and regulations, in addition to ten or more global conventions and protocols, govern the waste management sector in the country.Armenia's recent accomplishments in international accords include ratifying the Minamata Convention prohibiting the unregulated transit of mercury-containing products in 2017 (111).
In 2016, the country adopted the '2017-2036 Solid Waste Management System Development Strategy,' which proposes building nine new sanitary landfills, each serving a designated zone (112,113).In 2018, the administration decided to develop a waste processing factory in Hrazdan (114).Armenian civic society created 'Toprak Petq Chi' (or, 'I do not need a plastic bag') to limit single-use plastic bag usage.SmartApaga LLC commenced remunerated collection of recyclable waste in exchange for bonus points and discounts redeemable at project partners.Biomedical waste was treated differently.To avoid contamination and infection, wastes must be segregated at the point of generation.During the summer and winter in Armenia, medical waste is collected every 24 and 72 h.Garbage is incinerated at 1200-1500°C.Fly ash from incineration is disposed in government-affiliated pits for safe disposal (115).
The onset of the COVID-19 pandemic saw a shift in waste patterns, as the amount of waste generated from the residential regions increased compared to the industrial regions due to reduced production activities and lockdowns.The local communities in Yerevan set up separate collection bins for infected waste to reduce the spread of the virus, according to a survey conducted by the local NGOs in the region.In 2020, the United Nations reported that a substantial amount of medical waste was not treated following the existing regulation.In general, the foremost hospitals and medical institutes in the significant cities adhered to the requirements, but the medical centers in rural and urban areas were not effectively managed, resulting in uncontrolled bio-medical waste incineration and disposal (116).
The 2014 Waste Management Code aims to improve waste management practises by mandating construction and operation procedures that meet EU standards.In addition to the Minamata Convention on Mercury, Georgia has also joined the Stockholm Convention on Persistent Organic Pollutants and the Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their Disposal in addition to the Minamata Convention on Mercury.In 2016, Georgia adopted both a National Action Plan and a National Waste Management Strategy for 2016-2030 (117).The Action Plan plans for 30%, 50%, and 80% recycling of plastic by 2020, 2025, and 2030, respectively.Despite a few successful projects and an improved legal foundation, 300 hectares are occupied by 56 recognized landfills around the country (118).Medical waste was incinerated and disinfected prior to disposal.CENN reports that the majority of hospitals adhere to these requirements.Lack of financial and technical assistance inhibits rural and inaccessible medical facilities from complying with laws.During the epidemic, in addition to urging that face masks be disposed of in plastic bags, the Georgian government increased environmental penalties for medical and construction wastes by 25 times for people and 10 times for businesses (119).Georgia also took a significant step by adopting a national that aims to make the waste management industry autonomous by 2030 by instituting a system in which the people and corporate sector will bear all sector expenditures to strengthen the existing framework.Both Armenia and Georgia have the same  fundamental outlook when it comes to waste management, with landfilling serving the prime method being employed.Bio-medical waste treatment follows the same route in both countries, and although the onset of the pandemic introduced some new legislation, the basic idea remained the same.Apart from this, the nations are party to the Minamata Convention and adhere to the guidelines laid by the EU.The above factors justify clustering the countries into the same group, as seen in Figure 5.
China -Singapore (Group 2): The two emerging megacities from Asia, Singapore and Shanghai, have comparable developmental characteristics.The increasing rate of development in both cities brings with it the challenge of managing the massive quantity of waste generated daily.Although the waste generated in both cities varies by a considerable margin -9.84 million tonnes in Shanghai and 2 million tonnes in Singapore, the per capita waste generation is equal in both locations standing at 0.78 kgPerson −1 day −1 .The primary cause behind the high waste generation disparity per year is an increasingly high population in Shanghai compared to Singapore.Another similarity which has been observed between the two is the total  amount of waste which is recycled.In Shanghai (120), the total amount of waste recycled per capita amounts to 0.15, in Singapore (121), it is 0.12.The values as mentioned above aid in determining the efficiency of the waste management system in the respective countries.In the case of Shanghai, a recycling rate of 0.15 should be considered optimum given the land area covered and the city's population.However, the same cannot be implied for Singapore due to its comparatively lower land area and population.
Each municipality is working to enhance HSW management.In 2018, Shanghai recycled 20% of HSW whereas Singapore recycled 22%.As a result of COVID-19, waste management procedures changed, decreasing the amount of recyclable garbage.The four-segregation rubbish plan of Shanghai increased the efficacy of waste collection.Additionally, a recycling network was established to improve garbage recycling (120,122).Using a chute system, Singapore collects waste from multistory apartments, hence enhancing resident convenience.Both communities attempted to separate food trash from other waste to reduce contamination of recyclable waste (123,124).Also waste treatment and incinerator energy recovery was enhanced.Shanghai and Singapore are both capable of recovering 0.30 and 0.28 kWhperson −1 day −1 , respectively (121,125).Some items must be incinerated despite efficient waste management, resulting in flue gas emissions.Prior to the waste management program, Shanghai's global warming potential was 0.22 kg.CO2kg-1 waste while Singapore's was 0.29 kg.CO2kg-1 waste.The approach lowered the risk for global warming in both cities (126).This may determine the models' success in both sites.Nonetheless, China's landfills and Singapore's waste sorting system have room for development.
Argentina -Panama (Group 3): The Zero Waste Act (ZWA) of Buenos Aires, the capital city of Argentina, aims to protect the well-being of humans and the environment by raising public perception.Article No. 6 establishes a timeframe for progressively reducing solid waste disposal, which includes reducing the amount of garbage disposed off in landfills.Based on the amount of garbage collected by CEAMSE in 2004, the goals were to reduce it by 30% by 2010, 50% by 2012, and 75% by 2017.By 2020, both recyclable and reusable materials will be prohibited entirely.Articles 14 and 15 of the ZWA establish that generators are accountable for separating and implementing initiatives to mitigate the percentage of municipal solid waste.Producers must cover the collection cost and safe disposal of those packaging that cannot be reused, recycled, or composted, extending personal accountability until final disposal.However, no regulatory systems or incentives were provided.
The focus of Articles 19 and 20 of the ZWA is on stipulating that waste types would be separated for the purpose of remediation and eventual value.The city government was responsible for ensuring the supply of suitable waste collection bins in public.The legislation also mandates that the enforcement authority establish the collection rate based on whether the trash is dry or moist (127).To ensure their safety and cleanliness, all individuals participating in collection of MSW, must use appropriate PPEs.Wet garbage must be collected with closed-body trucks that limit volume and avoid leaks.The Act further stipulates that urban solid waste must be disposed of using landfill practises that do not impair the environment, global health, or safety, and that employ engineering requirements to contain the garbage in the lowest area possible.This substantially decreased its volume, forbidding open dumps, micro landfill foundations and watercourse discharge.
The Act seeks to explain facts and encourage the procurement of recyclable and reusable items to modify the behavior of the public through advertisements (128).In a similar context, a Zero Waste legislation of Panama was also released in March 2018.This legislation establishes an integrated waste management system based on the circular economy idea.The objectives are to maximize the economic, environmental, and social value of waste as natural resources, to provide new employment possibilities (including waste pickers), and to minimize pollution and its adverse effects on health and the environment.It also establishes obligations for all players (individuals, governmental and private sectors) that manufacture, import, market, consume, or dump the garbage.In addition, it establishes a National Education Program to foster a Zero Waste Culture (3Rs).Panama's Ministry of Environment began the Electronic Waste Project in October 2019 (127).A total of USD 5,50,000 has been set aside for its implementation between 2019 and 2024.The national government unveiled preliminary draughts of regulations governing used tyres, e-waste collection, and recycling during public events.Legislation targeting single-use plastics was introduced in 2019 to 'Regulating the Reduction and Progressive Replacement of Single-Use Plastics by 2021.

Conclusions
Improper management of MSW shadowed the public health services during COVID-19, which compelled the authorities to take decisive actions.Globally, the emergence of the pandemic had a substantial influence on the changing waste composition, obscuring efficient management of MSW.Prevalent contaminated healthcare wastes complicated solid waste management due to the presence of plastics with an inherent need for decontamination.disposal practices, such as large-scale microplastic pollution, lead to an environmental crisis.There was a subsequent change in protocols levied with the onset of the pandemicincineration was prioritized, thereby adding to the emission levels during the waste management process.Garbage collectors and frontline workers faced new occupational hazards due to a change in waste handling practices.Besides the health hazards posed due to handling contaminated wastes, the workers were susceptible to new forms of chemical hazards (such as furans and dioxins) released during the incineration process.Additionally, the personnel associated with the waste management sectors and sanitation were recorded to undergo psychological duress, social stigmatization, and social isolation.
Country-wise instances of improper solid waste management were reviewedthe cause of failure was assessed to be multi-variate.High population density, disparity amongst the socio-economic strata, ineffective policy implementation and tardy containment measures were some of the primary causative factors.Conversely, successful, and efficient solid waste management instances were also reviewed -flexibility of approach, swiftness of response, simple administrative guidelines and intelligent policy enforcement were pivotal for mitigating viral transmissions.Disinfection procedures during the pandemic were primarily focused on sterilizing facemasks to enable their reuse.Large-scale waste disinfection methods employed for MSW treatments were autoclaving, ozone treatment, UV-C treatment, dry-heating, microwave treatment, etc. Sustainable approaches were identified to manage the additional healthcare wastes originated during the COVID-19 pandemic.Exhausted PPEs and medical wastes were found to alleviate pre-existing waste valorization techniques however, these approaches were limited by their respective process capacities.The onset of the pandemic spearheaded the effective enforcement of waste management policies to combat pathogenic transmission through contaminated MSW.A thorough assessment of waste management policies suggested a correlation between waste composition and waste handling policies adopted.Subsequent rudimentary clustering studies were conducted to test the conceived hypothesis; instances of clusters were found with similar wastehandling policies.Although, the clusters were formed devoid of any socio-economic parameters, this study strives to indicate proof of concept and can serve as a precursor to advanced clustering studies.Future studies may focus on multi-variate approaches incorporating machine-learning-based clustering algorithms.Such a study may be the foundation for unified waste policy protocols and improve the response time and quality of response to unpredictable threats such as the COVID-19 pandemic.

Figure 1 .
Figure 1.Schematic representation of common publication key words imported from Scopus Index (as referred on 20th September 2022).

Figure 2 .
Figure 2. Global shift in waste composition between the of period 1980-2020 (Data collected from fig share data repository https:// figshare.com/).

Figure 4 .
Figure 4. Optimisation of number of clusters via Silhouette width method.

Figure 5 .
Figure 5. 2D scatter plot for clustering visualisation based on UN waste composition data.

Table 4 .
Comparison between the three different clusters selected based on different parameters.Parameter Case 1: Armenia -Georgia Case 2: China -Singapore Case 3: Argentina -Panama Measures Taken -Construction of sanitary landfills -Development of waste processing plant -Incineration of medical waste -Focus on Household Waste Management -Formation of recycling network -Incineration of waste to generate energy -Segregation of collection of waste -Use of landfills to store waste -Encompasses all the sectors Policies Framed -Campaign to avoid use of plastic -Autonomise waste handling industry -Party to Minamata Convention -Induction of four-segregation waste policy -Reduced contamination via segregation -Timeframe to reduce solid waste disposal.-Waste generators' responsibility to sort waste -Education program to foster zero waste culture Areas of Concern -Medical waste not treated as per norms -Unchecked waste incineration -Certain material must be incinerated -Increase in the number of landfill sites -Improvement of waste segregation -No regulatory systems in place or incentives -Provision of receptacles in the city -Open dump garbage disposal

Table 1 .
Percentage change in different waste types as compared to the waste composition in 1980 ('+' indicates increase and '-' indicates decrease in the percentage).