Water pollution refers to the contamination of water bodies (such as rivers, lakes, oceans, and groundwater etc.) by harmful substances or pathogens, making them unfit for human use or harmful to aquatic life. Water pollution comes from two sources: point or non-point sources. Point sources refer to a single identifiable source for the pollution, whereas non-point sources mean that the pollution comes from a variety of sources that are non-identifiable. There are numerous point and non-point sources, including industrial discharge, agricultural runoff, untreated sewage, and improper disposal of waste. The presence of pollutants in water can have serious environmental, health, and economic consequences.
Water pollution is a major environmental issue in India. India only holds about 4% of freshwater resources, yet nearly 70% of surface water in India is unfit for consumption. 163 million Indians lack access to safe drinking water and about 21% of communicable diseases are linked to poor quality water. The largest source of water pollution in India is untreated sewage. Other sources of pollution include agricultural runoff and unregulated small-scale industry. Most rivers, lakes and surface water in India are polluted due to industries, untreated sewage and solid wastes. Although the average annual precipitation in India is about 4000 billion cubic metres, only about 1122 billion cubic metres of water resources are available for utilization due to lack of infrastructure. Much of this water is unsafe, because pollution degrades water quality. Water pollution severely limits the amount of water available to Indian consumers, its industry and its agriculture.
Water resources of India India is one of the most water stressed countries in the world, with only 4% of freshwater resources. Water resources continue to dwindle, and while climate change is exacerbating this, there are issues of water pollution, which the following sections will tackle. In India, there are two main types of water resources: surface water and groundwater.
Surface water refers to the water in rivers, lakes, wetlands, and reservoirs. The main surface water bodies in India is the Ganges, Brahmaputra and the Barak, which account for 60% of the surface water in India. India divides its surface water into 22 basins. The Ganges is the longest river in India, flowing across 11 states, but India additionally has a variety of lakes, with nearly 1,000 large and medium-sized lakes.USAID. n.d. India Water Resources Profile Overview. Winrock International. https://winrock.org/wp-content/uploads/2021/08/India_Country_Profile-Final.pdf Groundwater refers to the water under the surface, stored in aquifers. This accounts for nearly 40% of usable water in India. Groundwater in India is classified into 14 system and these are subdivided into 42 major aquifers.
Quality of water resources
The Ganges
More than 500 million people live along the [Ganges] River.A Sacred River Endangered by Global Warming 17 June 2007 An estimated 2,000,000 persons ritually bath daily in the river, which is considered holy by Hindus. Ganges river pollution is a major health risk.India's polluted Ganges River threatens people's livelihoods DW Germany (2013)
NRGBA was established by the Central Government of India, on 20 February 2009 under Section 3(3) of the Environment Protection Act, 1986. It also declared Ganges as the "National River" of India."National Ganga River Basin Authority" The chair includes the Prime Minister of India and Chief ministers of states through which the Ganges flows."Composition of NGRBA."
The Yamuna
By an estimate by 2012, Delhi's sacred Yamuna river contained 7,500 coliform bacteria per 100cc of water. A number of NGOs, pressure groups, eco-clubs, as well as citizens' movements, have been active in their task to clean the river.Yamuna: Story of a river being poisoned to death. The Hindu on July 6, 2012 issue
Even though India revised its National Water Policy in 2002 to encourage community participation and decentralize water management, the country's complex bureaucracy ensures that it remains a "mere statement of intent." Responsibility for managing water issues is fragmented among a dozen different ministries and departments without any coordination. The government bureaucracy and state-run project department has failed to solve the problem, despite having spent many years and $140 million on this project.
Other Notable Rivers Buddha Nullah, a seasonal water stream, which runs through the Malwa region Jojari River, it is a river in Rajasthan polluted due to disposal of untreated industrial effluent in it Mithi River, which flows through the city of Mumbai, is heavily polluted. Mithi River, which has been degraded through industrial waste, but the Municipal Corporation of Mumbai has dedicated efforts to cleaning. Mula River, which has led to flash flooding due to the accumulation of waste at the banks of the river. Musi River, which is ranked the 22nd most polluted river in the world. Gomti River, which flows through numerous human settlements, contributing to pollution and waste. Vrishabhavathi River, which is heavily polluted because of the sewage drainage.
Organic matter In 2010, the water quality monitoring found almost all rivers with high levels of BOD (a measure of pollution with organic matter). The worst pollution, in decreasing order, were found in river Markanda (490 mg/L BOD), followed by river Kali (364), river Amlakhadi (353), Yamuna canal (247), river Yamuna at Delhi (70) and river Betwa (58). For context, a water sample with a 5-day BOD between 1 and 2 mg O/L indicates a very clean water, 3 to 8 mg O/L indicates a moderately clean water, 8 to 20 indicates borderline water, and greater than 20 mg O/L indicates ecologically unsafe, polluted water.CENTRAL POLLUTION CONTROL BOARD. 2011. Status of Water Quality in India 2011. https://nwm.gov.in/sites/default/files/waterwiki/1.pdf
The levels of BOD are severe near the cities and major towns. In rural parts of India, the river BOD levels were sufficient to support aquatic life.Kaur et al., Wastewater production, treatment and use in India UN Water (Publisher)
Coliform levels
Coliform levels indicate possible contamination from sources such as animal waste and sewage, and the goal of drinking water is to have 0 coliform levels. Rivers Yamuna, Ganga, Gomti, Ghaghara, Chambal, Mahi, Vardha and Godavari, are amongst the other most coliform polluted water bodies in India. For context, coliform must be below 104 MPN/100 mL, preferably absent from water for it to be considered safe for general human use, and for irrigation where coliform may cause disease outbreak from contaminated-water in agriculture.
In 2006, 47 percent of water quality monitoring reported coliform concentrations above 500 MPN/100 mL. During 2008, 33 percent of all water quality monitoring stations reported a total coliform levels exceeding those levels, suggesting recent effort to add pollution control infrastructure and upgrade treatment plants in India, may be reversing the water pollution trend.
Treatment of domestic sewage and subsequent utilization of treated sewage for irrigation can prevent pollution of water bodies, reduce the demand for fresh water in the irrigation sector and become a resource for irrigation.
Toxic metal contamination Toxic metal contamination from arsenic, lead, iron, and copper, is a common issue in India due to the geological composition and industrial waste. According to the Central Water Commission, in 2022, nearly 81 rivers and tributaries in India have found trace elements of heavy metal contamination. 43% of the river monitoring systems had alarming levels of one or more toxic metals. The Ganga River, was found to be the most polluted.
Causes of pollution In India, water pollution comes from a variety of point and non-point sources, affecting all bodies of water, including surface and groundwater. The main causes of pollution at industrial discharges, inadequate waste management, and agricultural runoff.
Untreated sewage
There is a large gap between generation and treatment of domestic waste water in India. The problem is not only that India lacks sufficient treatment capacity but also that the sewage treatment plants that exist do not operate and are not maintained. Sewage discharged from cities, towns and some villages is the predominant cause of water pollution in India. Investment is needed to bridge the gap between the sewage India generates and its treatment capacity of sewage per day. In urban India, everyday there is about 72.3 million litres of wastewater produced, but only 28% of this is actually treated. As these urban centers continue to grow, sewage systems in India will be unable to cope. The problem is compounded by a series of issues, mainly stemming from an inadequate waste management system. India generates approximately 62 million tonnes of waste in a year, which only about 80% is collected. The large amount of waste generated is unable to be processed, due to a lack of waste collection systems, lack of recycling facilities, and improper disposal practices. The rest of the waste ends up in the environment, including in water bodies in India. The sewage system and waste water treatment system is no better. The majority of the government-owned sewage treatment plants remain closed most of the time due to improper design or poor maintenance or lack of reliable electricity supply to operate the plants, together with absentee employees and poor management. The waste water generated in these areas normally percolates into the soil or evaporates. The uncollected waste accumulates in the urban areas causing unhygienic conditions and releasing pollutants that leach into surface and groundwater.
Sewage is not a waste product and it can be converted into wealth economically in a circular economy by using the aquatic life cycle of mosquitoes and non-biting midges. Organic matter in the sewage is consumed and transformed as adult mosquitoes and midges which can be used as fish/poultry meal.
When this waste gets into the water bodies, the high levels of carbon, nitrogen, and phosphorus stimulate microbial growth, which in turn depletes the oxygen leading to eutrophication, which is harmful to aquatic life. In the case of human health, the increased bacteria loads in water, can lead to dangerous diseases. A large number of Indian rivers are severely polluted as a result of discharge of domestic sewage, such as the Ganges, which is the largest river in India.
Agricultural run-off Since the Green Revolution, pesticide and fertilizer use in India has become commonplace, increasing food production, but additionally contributing to water pollution. In nitrogen based fertilizers, runoff has significantly impacted the water quality of the groundwater in India. Nitrate pollution is a primary concern in India, particularly for farming states such as Rajasthan, Karnataka, and Tamil Nadu. The overuse of these fertilizers has led to nearly 56% of India's districts exceeding the safe limit of nitrate in their groundwater.