Energy, drinking water and health nexus in India and its effects on environment and economy

This paper examines energy, drinking water and health nexus in India, and its consequences for the environment and economy. To establish this nexus, K-means cluster analysis and Davies–Bouldin validation index are employed to group 32 Indian states and union territories. The classification was performed based on 16 criteria, and the number of optimal clusters arrived at is 8. The nexus between energy, drinking water and health must be cautiously dealt with to ensure the social and economic growth of the nation. The criterion analysis of the states within these clusters indicates that states and union territories facing energy crises are usually deficient in safe drinking water services; consequently, people of those regions suffer from ill-health, which increases the economic burden on people through the loss of work productivity. With a deficient cash reserve, the communities are incapable of fulfilling the demand for energy and safe drinking water. However, while installing desalination plants to fulfil the need for safe drinking water, their environmental impact must be taken into account, as these systems have high energy consumption and significant environmental impact.


INTRODUCTION
As per the 2011 Census data, the nation has to fulfil all the necessary demands of more than 1,210 million people such as energy, food, water, education, health, employment, to attain effectual socio-economic progress (Jambhulkar et al. ). The nation is rapidly growing, with the fifth largest economy by nominal GDP in the world. Nominal GDP in the year 2019-20 was 209.19 lakh crore (Joshi et al. ).
To investigate the diversity and associated challenges in energy-drinking water-health issues in the states and union territories, these may be constituted into appropriate clusters. World Bank estimates that 21% of infectious diseases in India are related to the consumption of unsafe water, and diarrhoea alone causes more than 1,600 deaths daily. To handle these challenges, two basic requirements, access to clean energy and safe drinking water to every individual, must be fulfilled by the central and state governments (Ambade et al. ).
From the various reports published by the Government of India, associated with energy accessibility, safe drinking water availability, and public health, it has been observed that these are critically interlinked factors, forming a multifaceted nexus issue. It is commonly noticed that people facing energy crises are usually short of safe drinking water services, and hence they suffer from waterborne diseases. Consequently, they bear a loss of work productivity and earnings. With a low income, people are unable to fulfil the demand for energy and safe drinking water, as shown in Figure 2.
This nexus issue has to be dealt with comprehensively to boost countries' economic growth as well as to reduce poverty. The literature shows that many investigators across the globe have used the nexus approach to solve significant crises of society. Avatar et al. () investigated the population-urbanisation-energy nexus and concluded that the use of science and technology is required at the policy level, the geographical location of energy resources affects energy distribution and its cost. Rasul () demonstrated the food-water-energy nexus. Authors have depicted that free water and subsidised power is not sufficient for rural and slum development. Kro () studied the nexus of water-poverty-health expenditure and stated that poor people are prone to suffer from toxic substances through drinking water, as they cannot afford water of good quality for drinking and cooking. Bidoglio et al. ()  () demonstrated the water-energy-food nexus and concluded that organised action for integrating the water and food requirement into energy scheduling at the neighbourhood level is vital to avoid trade-offs and to improve progressive outcomes and impact of power ventures. Wicaksono & Kang () gave a water-energy-food nexus for optimisation of resource allocation to maximise the security of resources. Review of the literature shows that the interlinking of energy, drinking water and human health in the Indian context is not holistically dealt with by any investigators to handle the problem of energy and safe drinking water security for the sustainable development of the nation. The present work investigates the energy, drinking water and health nexus in India using a clustering approach.
The paper describes the existing energy, drinking water and people's health scenario in the Indian context, interlinking factors between energy, drinking water and health using numerical indices and K-means clustering algorithm. The paper also provides information on water desalination, its environmental impact and the cost associated with desalinated water. Finally, the work concludes with region-wise investigations and policy recommendations.

METHODOLOGY AND DATA COLLECTION
To find appropriate literature on energy scenarios, clean drinking water availability, its access to people and public health in India, relevant research papers have been collected and studied to understand the nexus between energy, drinking water and health in the nation and its implications for climate change. Special attention has been given to internationally published reports on India from various distinguished organisations such as the UN, WHO, UNICEF, IEA, IRENA, IEEJ and Government of India dealing with energy, drinking water and health, with their policies and guidelines to discover their relevance for this proposed nexus study.
Collected research papers and reports have been interpreted carefully, and the most significant findings of each one are noted down. The state-wise data are collected from the portals of Government of India such as geographical area, population (urban, rural), GDP, literacy rate, people living below the poverty line, primary energy mix, cases and deaths reported due to waterborne diseases, electrification done, per capita energy consumption, human development index, people with access to clean cooking fuel, total annual replenishable groundwater resources and public expenditure on health (refer to Tables 1 and 2). and health-energy to compile diverse sections in the paper. Finally, the nexus between energy, drinking water and health has been established. Figure 3 shows the steps used to carry out this study, which is selfexplanatory.

PRESENT ENERGY SCENARIO OF THE NATION
As per the report of the Economic Survey of India (), presently India consumes only 6% of the world's primary energy to fulfil the energy demand of more than 1,300 million people. The nation has low per capita energy consumption (1,181 kWh per person per year or 140 W per person in 2019) which is less than half of the world's This survey report states that India, home of 18% of the world's population, aims to reduce its energy poverty sustainably, to attain economic growth, and to control environmental pollution below the internationally set benchmark. This report forecasted that the total energy demand of India would increase by 25% by 2040, which will exert enormous pressure on natural energy resources.
To attain these objectives, the government of India sets ambitious goals such as (NITI Aayog & IEEJ ): • installation of renewable energy capacity to 175 GW by 2022, • 24 × 7 electricity to all households by 2022, • residential housing to all by 2022, • development of 100 smart cities, • 10% reduction of oil and gas imports by 2022 as compared with import demand in 2014-15, • provision of clean cooking fuels to all. Figure 4 shows that a large proportion of the energy demand of the nation is fulfilled by burning coal. The use of natural gas is found to be less (6.51%) as compared with the rest of the world (23.82%). The share of coal in the primary energy mix for India and the world is 58 and 29%, respectively, whereas that of natural gas is 6.5 and 24%, respectively. Uses of other energy sources for electricity generation are found to be almost the same in the primary energy mix of the nation and the world. However, it has been projected that the nation has a lot of potential to increase the share of natural gas in its primary energy mix (Tiewsoh et al. ). Figure   2047. The Indian urban population will grow from 31% (2011) to 51% (2047). The increasing population of the nation will increase the burden on energy resources, and fossil fuel import expenditure (Katekar & Deshmukh a). At the same time, the energy demand of industry would increase from 16% (2011) to 34% (2047). The forecasted primary energy mix of the nation in 2047 is shown in Figure 6. It shows that coal will remain the dominant fuel in the primary energy mix in 2047 with 40% of the contribution, followed by oil with 27.62% of the share (NITI Aayog & IEEJ ).
As compared with the primary energy mix of 2011, the contribution of nuclear, renewable, oil and natural gas will increase by 3, 3, 2 and 2%, respectively; however, the contribution of coal and agricultural waste will be reduced by 7 and 4%, respectively, as shown in Figure 7. The nation's own fossil fuel reserves are depleting rapidly, which will alter the fossil fuel import dependence, as shown in Figure 8 (NITI Aayog & IEEJ ).

PRESENT DRINKING WATER SCENARIO IN INDIA
Safe drinking water scarcity is one of the significant difficulties in India. India has 4% of the world's freshwater resources to meet the demand of more than 1,300 million people (Katekar & Deshmukh b).  presently, no Indian city can provide 24 × 7 water supplies to its entire urban population. As per the Census 2011, the government is attempting to supply treated tap water, but its proportion is drastically variable across the nation (0.9-99.6%). Figure 10 shows the locations where the treated tap water supply is less than 25% (Eris et al. ).
The expected water demand-supply gap will be 50 BCM for the domestic sector by 2030, and industrial water demand will increase by three times by 2030. Another big challenge is that 40% of India's thermal power plants are situated in water-stressed regions, and of them, 70% of power plants will face high water stress by 2030. Presently, 11% of Indian land is desertified due to water shortages.
Eighty-two per cent of the rural households in India do not have an individually piped water supply system at their home. Seventy per cent of India's surface water is    defined five different water service levels for community drinking as shown in Figure 11.

HEALTH AND WATERBORNE DISEASES
A report of WHO () declares that safe and readily accessible drinking water is vital for public health, whether it is used for cooking, drinking or recreational purposes. The Institute of Medicine recommends that a man must consume roughly 3.7 litres, and a woman must drink 2.7 litres of potable water per day to maintain good health (Abbaspour ).
High water pollution makes the task of potable water supply to the communities extremely difficult. The quality of drinking water is altered in many ways, such as changes in nutrients, sedimentation, and by addition of compounds such as heavy metals, non-metallic toxicants, persistent organics and pesticides (Chouler & Di Lorenzo ).   The WHO states that the maximum permissible limit of salinity in drinking water is 500 ppm, and for exceptional cases, it may be up to 1,000 ppm. However, most of the surface or groundwater available on Earth has salinity up to 10,000 ppm. Seawater usually has a salinity in the range of 35,000-45,000 ppm (El-Ghonemy ). In addition to this, pollutants in water come in many forms such as deoxygenating materials, toxic materials, and solid materials such as vehicle tyres, shopping trolleys, old shoes, and plastics.
These pollutants severely affect biological conditions in water and also deoxygenate the water. Such infected water transmits severe diseases. Figure (228), and the lowest cases were found in Rajasthan (2)   The highest public health expenditure is found for Uttar Pradesh (Rs. 189,671,521).

ESTABLISHMENT AND INVESTIGATION OF E-DW-H NEXUS
Nexus is the relationship between two or more entities. The nexus approach has been used by many researchers to solve significant problems of societies. To establish and judge the nexus between some factors, some measurable parameters called nexus indices need to be estimated. This section defines nexus indices, evaluates their magnitude and establishes the nexus among them.

Energy index (E)
The average value of an entity per person per year is termed as per capita. Energy consumption per capita indicates the total energy consumed per person per year in the nation. The energy index of a state or union territory is the ratio of per capita energy consumption of a state or union territory to the per capita energy consumption of the nation. A higher value of energy index (E) is always desirable, which indicates better accessibility of energy to people of that region.

E ¼ Per capita energy consumption of state Per capita energy consumption of country
(1)

Drinking water index (W)
Drinking water index (W) indicates the fraction of the total population that does not have access to safe drinking water.
Its magnitude varies between 0 and 1. A lower value is always desirable, as it indicates a smaller number of people of a given state/union territory without access to safe drinking water.
W ¼ Total population without acesss to safe drinking water Total population of state=UT (2)

Health index (H)
Health index (H) indicates the fraction of the total population suffering from waterborne diseases. Its value varies from 0 to 1. This index must be as low as possible. Its lower value indicates a smaller number of people of a given state/union territory suffering from waterborne diseases.
H ¼ Total population suffering from waterborne diseases Total population of state=UT To establish the nexus between energy, drinking water and health, the above indices are calculated for different states and union territories and are shown in Table 2  Data sets are iteratively moved from one group to another on this basis until the specified termination criterion is met (Chen et al. ). The total square error value D K for cluster K is the sum of the errors from the individual clusters (Dunn ). Cluster validity analysis platform (CVAP) is used for the algorithms (Wang ). K-means is iterated for three to ten clusters. Table 3 presents states in each sub-cluster and their numbers. It is observed from Figure 14 that the sum of squared errors decreased from 16.39 to 6.02, with the increase in the number of clusters. It has been observed from Table 3 that with the increase in the number of clusters, only one state exists as a sub-cluster.
The reason behind this is that it contains a higher value of either energy or drinking water or health index. For example, in cluster 4, UP holds an independent sub-cluster.
Another research question is, what is the optimal size of clusters for chosen N data sets? In this regard, cluster validation algorithms play a significant role (Raju et al. ).

Davies-Bouldin is chosen in the present study to serve the purpose (Davies & Bouldin ; Raju & Nagesh Kumar
). In the present study, the Davies-Bouldin validation index provided the optimal cluster size of 8, as shown in Figure 15.

Energy-drinking water-health nexus
Energy, drinking water and health indices tabulated in Table 3 are compared for different states and union territories to investigate the nexus between them. This section discusses the interlinking of energy and drinking water, drinking water and health, as well as energy and health. Finally, the nexus between all these factors is also elaborated.

Interlink of energy and drinking water
The International Energy Agency (IEA) () outlines energy access as a reliable and affordable supply for both clean cooking facilities and electricity, which is sufficient to operate essential energy services (Bhujade et al. ).
Lack of energy access results in poor access to clean drinking water. Consequently, people are not able to use desalination systems, or they prefer not to use boiled drinking water daily. Thus, neglecting the contamination in drinking water, people use freely available water to fulfil their daily water demand for cooking and drinking. Figure 16 shows

Interlink of drinking water and health
Water accessibility is defined as how the community or individual families practically access drinking water. All living beings from the water to land need water intake to avoid dehydration, but consumption of contaminated water is harmful and can lead to fatalities. Figure  and Chandigarh (CH) have better access to safe drinking water, yet, higher numbers of cases of waterborne diseases are registered.

Interlink of energy and health
Energy is the critical element for the socio-economic development of every community. All types of energy require water for their production, directly or indirectly; energy is needed to supply drinking water to communities. Thermal/electric energy is essential for the desalination of impure water. Nature-based technology for water purification is not usually suitable on a large scale as the quality of drinking water cannot be assured. Figure 18 shows that       consequently, people of those regions suffer more from illhealth due to drinking infected water, which increases the economic burden on them through the loss of work   productivity. With a deficient cash reserve, the communities are incapable of fulfilling the demand for energy and safe drinking water. Hence, this nexus must be carefully dealt with to gain the social and economic growth of the nation.

EFFECT ON CLIMATIC CHANGE
To provide sufficient and safe drinking water to more than 1,300 million Indians is a significant challenge as water demand is increasing rapidly day by day due to population growth, industrialisation and urbanisation. Water pollution and climate change have affected the natural hydrological cycle that also generates water scarcity (Cheng et al. ).
The government is taking several steps to improve the drinking water supply to people, such as water conservation, advancement in water collection and distribution systems, periodic repair and maintenance of water supply infrastructure. These efforts improve the quality of existing water resources. Another alternative to increase the drinking water supply is water desalination and water reuse (Elimelech & Phillip ). Table 5 shows that RO is the most energy-efficient technology, and its added advantage is that it does not consume any thermal energy; hence, its environmental impact is lowest as compared with other methods of desalination. Forward osmosis is also an emerging technology, but it consumes heat energy in addition to electric power.  (Leach & Deshmukh ). It is estimated that nearly 0.71 kWh of energy is required for a desalination process to produce 1 cubic metre of freshwater from brackish water; subsequently, this results in the burning of at least 1 ton of oil to produce 20 tons of desalinated water, which places an enormous burden on the environment (Reddy & Sharon ). Another problem with conventional desalination is  the disposal of desalination by-products. Their salinity is about twice that of untreated saline water. Concentrated brine, chemicals used in pre-treatment and membrane-cleaning exert high environmental risks to living organisms when these by-products are discharged into rivers or seawater (Elimelech & Phillip ).
To reduce the burden of fossil fuel expenditure and its environmental impact on desalination, renewable energy is a viable solution (Katekar & Deshmukh c). Figure 21 shows    with photo-voltaic powered seawater desalination using a reverse osmosis (PV/SW-RO) system will be about US$ 1.21 m 3 while it will be between US$ 1.18 and 1.56 for conventional RO desalination. Table 7 shows various renewable energy-driven water desalination systems with their energy consumptions and the cost of production water.
In the Indian context, it is usually observed that the poor often pay high costs for energy; sometimes, they do not have

SUMMARY AND CONCLUSIONS
This study investigates the energy, drinking water and health nexus in India, keeping in view its critical role in climate change. This review has been summarised, and the subsequent conclusions have been drawn: • The total number of people suffering from waterborne diseases in the nation from 2014 to 2016 was 16,288,959 and 2,498 deaths occurred due to consumption of contaminated water.
• The average value of energy, drinking water and health index for the nation is estimated at 0.97, 0.21 and 0.03, respectively.
• It has been found that states/union territories facing energy crises usually are deficient in safe drinking water services; consequently, people in those regions suffer more from waterborne diseases, which increases the economic burden through the loss of work productivity.
With a deficient cash reserve, the communities are incapable of fulfilling the demand for energy and safe drinking water.
As far as the authors are aware, this is the first study where the K-means clustering algorithm, along with the Davies-Bouldin index, is applied to the classification of 32 Indian states based on 16 criteria. Observations that can be made from the study are: • Sum of squared error decreased from 16.39 to 6.02.
• Eight clusters are found to be suitable based on the Davies-Bouldin index approach.
• It should be noted that the observations derived are based on data collected from various sources, selected clustering related algorithms and views of authors.
From this assessment, it has been recognised that there is a substantial nexus between energy, drinking water and health, which must be carefully dealt with to gain the social and economic growth of the nation.

Recommendations
To combat the problem of safe drinking water scarcity, the following are some recommendations: • To provide safe drinking water to all, multilevel governance, the involvement of local non-government organisations (NGOs) and active public participation are crucial for the formulation of national and regional water policies.
• To increase safe drinking water affordability to the ordinary family, the cost of water provision services must be reduced. It can be possible using technological innovation, improvement in water supply management, good governance, increasing transparency in water distribution, and efficiency improvement of water desalination systems.
• The government should support efforts to raise awareness of the importance of preserving water resources and support studies to monitor drinking water quality and alternative treatment methods.
• Production of freshwater using renewable desalination technology is a workable solution in remote areas that lack conventional energy sources like heat and electricity.
• Economical solar distillation, as well as solar desalination systems, must be developed to provide clean and safe drinking water at the doorstep of people residing in rural and remote areas.