The ongoing pollution of the Ganges, the largest river in India, poses a significant threat to both human health and the environment. The river supplies water to approximately 40% of India's population across 11 states and serves an estimated 500 million people—more than any other river in the world.

Several initiatives have been undertaken to clean the river, but they have failed to produce significant results.Ganga, Yamuna banks cleaned 12 November 2013 After being elected, India's Prime Minister Narendra Modi pledged to work on cleaning the river and controlling pollution. Subsequently, in the June 2014 budget, the government announced the Namami Gange project. By 2016, an estimated ₹30 billion (US$460 million) had been spent on various efforts to clean up the river, with little success.

The proposed solutions include demolishing upstream dams to allow more water to flow into the river during the dry season, constructing new upstream dams or coastal reservoirs to provide dilution water during the dry season, and investing in substantial new infrastructure to treat sewage and industrial waste throughout the Ganges' catchment area.

Some suggested remedies, such as a coastal reservoir, would be very expensive and would involve significant pumping costs to dilute the pollution in the Ganges.

Causes The main causes of water pollution in the Ganges River are the disposal of human sewage and animal waste, increasing population density, and the discharge of industrial waste into the river.

Human waste The river flows through 100 cities with populations exceeding 100,000 residents, 97 cities with populations between 50,000 and 100,000 residents, and about 48 towns. A large proportion of the sewage with a high organic load in the Ganges originates from domestic water usage by this population. Three-quarters of all the sewage generated in the northern plains remains completely untreated before being discharged into the Ganges and its tributaries. Even where effective sewage treatment plants have been provided, more than half are either not operating at all or not operating efficiently. A review in 2022 indicated that only 37% of the 72,368 million liters per day (ML/D) of sewage generated is treated.

Industrial waste There are numerous industrial cities on the banks of the Ganges, such as Kanpur, Prayagraj, Varanasi, and Patna, along with tanneries, chemical plants, textile mills, distilleries, slaughterhouses, and hospitals. These cities and facilities actively contribute to the river's pollution by dumping untreated waste into it.

One coal-based power plant on the banks of the Pandu River, a Ganges tributary, burns 600,000 tons of coal each year and produces 210,000 tons of fly ash. The ash is dumped into ponds, where a slurry is filtered, mixed with domestic wastewater, and then released into the Pandu River. Fly ash contains toxic heavy metals such as lead and copper. The concentration of copper in the Pandu River, before it even reaches the Ganges, is a thousand times higher than in uncontaminated water.

Industrial effluents account for about 12% of the total volume of waste reaching the Ganges. Although this is a relatively low proportion, it is a major concern because these effluents are often toxic and non-biodegradable. Plastic and industrial waste, including wastewater from factories on the banks of the Ganges, are also significant sources of pollution. The most alarming issue facing the river is its increasing lack of water, which is being used for irrigation faster than it can be replenished.

Religious traditions Owing to the sacred status of the river in Hinduism, over 70 million Hindu people bathe in the Ganges to cleanse themselves of their past sins, during festive seasons. Some materials, such as food, waste, and leaves, are left in the river, contributing to its pollution.

In the Hindu holy city of Varanasi alone, an estimated 40,000 bodies are cremated each year and deposited into the Ganges. Because many families cannot afford the high cost of sufficient quantities of cremation wood, many of the bodies placed in the river are only half-burnt.Wohl, Ellen E. 2012. A world of rivers: environmental change on ten of the world's great rivers. Chicago: University of Chicago Press.

Dams and pumping stations Built in 1854 during British rule in India, the Haridwar Dam has contributed to the decay of the Ganges by significantly reducing the river's flow. The Farakka Barrage was initially constructed to divert fresh water into the Hooghly River but has since increased salinity in the Ganges, adversely affecting groundwater and soil along the river. The barrage has caused major tension between Bangladesh and India, with Bangladesh actively considering the construction of the Ganges Barrage Project to address the salinity issue. Despite a government-commissioned green panel report recommending the cancellation of 34 proposed dams due to environmental concerns, the Indian government plans to construct about 300 dams on the Ganges and its tributaries in the near future.

Three additional dams across the Ganges River are located at Bijnor, Narora, and Kanpur. The dams at Bijnor and Narora divert all the water, including base flows during the dry season, to canals for irrigating areas up to Allahabad city. Flow upstream of the Kanpur barrage is used during the dry season for the drinking water supply of cities. Downstream of the Kanpur dam, adequate water volumes are unavailable during the dry seasons of the year.

Several pumping stations are located on the banks of the Ganges downstream of the Kanpur barrage, serving the region's irrigation needs.

These large pump houses are situated at the following coordinates:

Rukunpur: 26°10′21″N 80°38′57″E Kanjauli Kachhar: 25°17′37″N 82°13′15″E Hakanipur Kalan: 25°12′57″N 83°01′15″E Bhosawali: 25°20′46″N 83°10′11″E Shekpur: 25°32′13″N 83°11′57″E Chochakpur: 25°28′55″N 83°25′11″E Lamui: 25°23′20″N 83°32′11″E Chausa: 25°31′11″N 83°54′04″E

These irrigation facilities pump out most of the base flows from the main river downstream of Kanpur city.

To keep the Ganges flowing and dilute polluted water inflows from habitations and industries, a minimum environmental flow of at least 5,000 cusecs is required from Narora to Farakka during the eight-month-long dry season. This could be achieved by constructing storage reservoirs with a capacity of 100 Tmcft across the Ganges' tributaries upstream of Narora city and reserving the stored water solely for minimum environmental flows.

Additionally, a series of cascading dam bridges should be constructed across the river from Kanpur to Allahabad to increase the surface area of impounded polluted water and serve as natural oxidation ponds. The goal is for the accumulated pollutants to be washed away during the annual monsoon floods. Several dams are already planned between Farakka and Allahabad as part of the National Waterway 1 project, which aims to make the 1,620 km stretch of the river navigable from Haldia to Allahabad and could potentially be extended up to Kanpur.

Statistics A 2006 measurement of pollution in the Ganges revealed that river water monitoring over the previous 12 years had shown fecal coliform counts of up to 100,000,000 MPN per 100 mL and biological oxygen demand levels averaging over 40 mg/L in the most polluted part of the river at Varanasi. The overall rate of water-borne disease incidence, including acute gastrointestinal diseases, was estimated to be about 66%.Hamner S, Tripathi A, Mishra RK, Bouskill N, Broadaway SC, Pyle BH, Ford TE. "The role of water use patterns and sewage pollution in incidence of water-borne/enteric diseases along the Ganga river in Varanasi, India.", International Journal of Environmental Health Research, Montana, USA, 2006 Apr 16.

A systematic classification by the Uttarakhand Environment Protection and Pollution Control Board (UEPPCB) categorized river waters into four categories: A (safe for drinking), B (safe for bathing), C (safe for agriculture), and D (excessive pollution). The Ganges was classified in category D. Coliform bacteria levels in the Ganges have also been tested at 5,500 MPN per 100 mL, a level too high to be considered safe for agricultural use, let alone for drinking or bathing.

The leather industry in Kanpur, which employs around 50,000 people in more than 400 tanneries, uses chemicals such as toxic chromium compounds. Despite the establishment of a common treatment plant in 1995, chromium levels in the Ganges have not decreased and now exceed the recommended maximum level by more than 70 times.

A study conducted by the National Cancer Registry Program (NCRP) under the Indian Council of Medical Research in 2012 suggested that "those living along its banks in Uttar Pradesh, Bihar, and Bengal are more prone to cancer than anywhere else in the country."

In 2020, a study showed that the levels of toxic heavy metals in the Ganges had significantly improved in recent years. This study was supported by the Indo-US Science and Technology Forum (IUSSTF).

Effects

Marine life The results of mercury analysis in various specimens collected along the basin indicated that some fish muscles accumulated high levels of mercury, with approximately 50-84% of it being organic mercury. A strong positive correlation was found between mercury levels in muscle tissue and both food habits and fish length.Moumita Pal, Santinath Ghosh, Madhumita Mukhopadhyay, Mahau Ghosh. Ganga and Yamuna. "Methyl mercury in fish—a case study on various samples collected from Ganga river at West Bengal.", Environmental Monitoring and Assessment, 8 June 2011.

The Ganges river dolphin is one of the few species of freshwater dolphins in the world. Listed as endangered, its population is believed to be less than 2,000. Hydroelectric and irrigation dams along the Ganges, which prevent the dolphins from traveling up and down the river, are considered the main reason for their declining numbers.

The Ganges softshell turtle (Nilssonia gangetica) is found in the Ganges, Indus, and Mahanadi river systems of Pakistan, India, Bangladesh, and Nepal. This turtle inhabits deep rivers, streams, large canals, lakes, and ponds with beds of mud or sand. According to the International Union for Conservation of Nature, this turtle species is vulnerable. Due to their long lifespan and high trophic level in the aquatic food web, these turtles are particularly susceptible to heavy metal pollution, a major issue in the Ganges.Malik, R. N., Ghaffar, B., & Hashmi, M. Z. (2013). Trace metals in Ganges softshell turtle (aspideretes gangeticus) from two barrage: Baloki and rasul, pakistan. Environmental Science and Pollution Research International, 20(11), 8263-73.

Wildlife Some of the dams being constructed along the Ganges basin will submerge substantial areas of nearby forest. For example, the Kotli-Bhel dam at Devprayag will submerge 1,200 hectares of forest, destroying the forest ecosystem and its wildlife.

Humans An analysis of Ganges water in 2006 and 2007 revealed significant associations between water-borne diseases and the use of the river for bathing, laundry, washing, eating, cleaning utensils, and brushing teeth. Water from the Ganges has been linked to dysentery, cholera, hepatitis, and severe diarrhea, which remains one of the leading causes of death among children in India. During the summer and monsoon, hospital wards teem with children who need treatment for waterborne diseases - but according to S.C. Singh, a paediatrician at Varanasi Shiv Prasad Gupta Hospital, their parents rarely mention that they have been swimming in the river. They don't appear to have made the connection, he says.

Cleanup efforts Ganga Mahasabha