Indian Rivers: Pollution's Main Causes And Effects

India's rivers are facing a severe threat in the form of pollution. The country's vast river systems support the survival of millions of people and are home to 18% of the world's unique aquatic plants and animals. However, a little over half of India's 605 rivers were found to be polluted in 2022, with the largest source of water pollution being untreated sewage. Industrial and municipal waste, agricultural runoff, and urbanisation are also key contributors to the pollution of Indian rivers.

Untreated sewage and industrial waste

Untreated sewage is the largest source of water pollution in India. According to a 2013 report by the Centre for Science and Environment (CSE), 80% of Indian sewage is untreated and flows directly into the nation's rivers, polluting the main sources of drinking water. The report also states that Indian cities produce 38,354 million litres of sewage per day, while the urban sewage treatment capacity is only 11,786 million litres per day. This gap between sewage generation and treatment capacity results in untreated sewage being dumped into rivers, causing severe water pollution.

The problem is exacerbated by the inadequate infrastructure for sewage treatment in India. Many government-owned sewage treatment plants remain closed due to improper design, poor maintenance, power supply issues, and management problems. This leads to untreated sewage percolating into the soil or evaporating, eventually finding its way into rivers and other water bodies. The sewage discharged from cities, towns, and villages is the predominant cause of water pollution in India, with high levels of faecal coliform and biological oxygen demand (BOD) reported in many rivers, including the Ganga.

Industrial waste is another significant contributor to river pollution in India. Large industrial enterprises discharge untreated wastewater directly into rivers, worsening the condition of the water. The Ganges River, considered holy and pure in Indian culture, has become one of the most polluted waterways in the world due to industrial waste and sewage. In addition to sewage, the Ganges receives waste from tanneries, chemical plants, textile factories, slaughterhouses, and hospitals, which further degrades the water quality. The Central Pollution Control Board has identified industrial effluents, hazardous waste, and biomedical waste as key reasons for the Ganga's pollution in West Bengal.

The pollution of Indian rivers has severe consequences for the environment and public health. The introduction of agrochemicals and pesticides and untreated sewage brings chemicals, heavy metals, and high levels of nitrates into the water, causing bioaccumulation and potential carcinogenic and mutagenic effects. The high levels of pollution in rivers like the Ganga and Yamuna have led to the spread of waterborne diseases, including acute gastrointestinal illnesses and cholera, malaria, and tuberculosis.

To address the issue of untreated sewage and industrial waste in Indian rivers, the Indian government has taken several initiatives. The government has encouraged the implementation of Zero Liquid Discharge (ZLD) technology in industries to eliminate liquid waste. Additionally, the government launched a $4 billion campaign to prevent untreated sewage from entering the Ganges by 2020 and sought the closure and relocation of industries along the river. While these efforts are a step in the right direction, more comprehensive measures and stricter enforcement of environmental laws are necessary to mitigate the impact of untreated sewage and industrial waste on Indian rivers.

Poor waste management and lack of infrastructure

The majority of government-owned sewage treatment plants in India remain closed or operate below capacity due to design flaws, maintenance issues, unreliable electricity supply, and poor management. This leads to the accumulation of uncollected waste in urban areas, which eventually finds its way into rivers and contaminates both surface and groundwater. The treatment capacity falls far short of the amount of sewage generated, particularly in major cities, resulting in the discharge of untreated waste into water bodies.

Inadequate solid waste management is another significant issue. India's Solid Waste Management Rules mandate source segregation of waste and require state governments to ensure compliance. However, biodegradable components of municipal solid waste (MSW) are often not segregated, leading to mounting mixed waste that cannot be incinerated and ends up in dumpsites and landfills. The lack of circular waste management systems further contributes to the waste leakage into rivers.

The pollution of Indian rivers is also attributed to industrial activities, with untreated industrial effluents and runoff contaminating the water. Rivers like the Damodar, which passes through India's industrial heartland, face severe pollution from industrial waste. Additionally, coal mining activities in the Damodar basin contribute to soil erosion and the introduction of sediments and pollutants into the river.

The consequences of poor waste management and lack of infrastructure are dire, posing threats to both the environment and human health. The pollution of Indian rivers has led to the degradation of aquatic ecosystems and the loss of unique aquatic plant and animal species. It also endangers the health of the millions of people who depend on these rivers for their survival, with fatal diseases such as cholera, malaria, and tuberculosis developing in polluted river stretches.

Agricultural runoff and agrochemicals

During the monsoon season, or any period with significant rainfall, fertilisers and pesticides are washed into nearby water bodies. These non-point sources of pollution enter the river basin at multiple dispersed points, making it difficult to pinpoint and address the exact sources of contamination. The excessive nutrients and sediment from agricultural activities alter the natural function of wetlands, leading to habitat losses for various plant and animal species.

The introduction of agrochemicals, such as Dichlorodiphenyltrichloroethane (DDT), Aldrin, and Hexachlorocyclohexane (HCH), poses a significant threat to Indian rivers. Despite being banned worldwide due to their environmental impact, these chemicals are still used in India due to their low cost and easy availability. DDT, for example, has been consumed in India at a rate of over 350,000 million tonnes since 1985, even though it was outlawed in 1989. The persistence of these chemicals in the environment leads to bioaccumulation, posing potential carcinogenic and mutagenic risks to both aquatic life and humans.

Riverine nitrogen runoff in India is highly sensitive to changes in precipitation and the intensification of seasonal monsoons. Increased fertiliser use has impacted groundwater and atmospheric emissions, and the lack of data on wastewater effluent discharged into agricultural lands makes it challenging to fully understand the extent of the problem.

Agricultural runoff also introduces various pollutants into the water, including heavy metals, oils, asphalt, sediments, and chemicals. These contaminants can have detrimental effects on aquatic ecosystems, reducing water quality and harming marine life.

Soil erosion and deforestation

Agricultural plants such as coffee, cotton, palm oil, soybean, and wheat are often unable to hold onto the soil, exacerbating the problem. As a result, the soil is swept into rivers, clogging them with sediment and leading to increased pollution, declines in fish populations, and negative impacts on other species.

Deforestation also contributes to climate change, desertification, fewer crops, flooding, and an increase in greenhouse gases in the atmosphere. The loss of trees and vegetation can also have detrimental effects on Indigenous peoples and local communities.

In the context of Indian rivers, soil erosion and deforestation have severe consequences. For example, the Ganga, Yamuna, and Godavari rivers are among the most polluted in India, with high levels of sewage, industrial waste, and agricultural runoff. Soil erosion further exacerbates the problem by adding sediments and pollutants to the water, degrading water quality, and limiting the amount of water available for consumption, agriculture, and industry.

To address these issues, sustainable land use practices, reforestation efforts, and improved wastewater treatment systems are necessary. By preserving and restoring critical habitats, protecting watersheds, and treating domestic wastewater, India can mitigate the impacts of soil erosion and deforestation on its river systems.

Urbanisation and industrialisation

Urbanisation has led to an increase in municipal waste, which has been a major source of river pollution. This includes untreated sewage, solid waste, and industrial effluents discharged into rivers. Many Indian cities and towns lack proper sewage treatment plants and waste disposal mechanisms, resulting in the discharge of untreated waste into rivers. For example, a 2019 assessment found that more than 70% of towns along the Ganga river were directly disposing of their waste into the river due to a lack of adequate infrastructure. This has led to the contamination of water with harmful chemicals, heavy metals, and pathogens, posing serious risks to human health and aquatic ecosystems.

Industrialisation has also played a key role in river pollution, with industrial discharge along riverbanks contributing a range of pollutants. Industrial activities, particularly in unregulated small-scale industries, have released untreated industrial effluents, including toxic chemicals and heavy metals, directly into rivers. The Damodar river, for instance, passes through an industrial heartland and has been severely polluted by untreated industrial waste. Additionally, coal mining activities in the Damodar basin have contributed to soil erosion and the introduction of sediments and pollutants into the river.

The combination of urban and industrial waste has led to a degradation of water quality in Indian rivers, with high levels of biological oxygen demand (BOD) and faecal coliforms. This has resulted in the contamination of drinking water sources, impacting millions of people who depend on these rivers for their water needs. It has also disrupted aquatic ecosystems, affecting the health of unique aquatic plants and animals found in Indian river systems.

To address these issues, the Indian government has launched several initiatives, such as the National Mission for Clean Ganga (NMCG) and the Namami Gange programme, which aim to rejuvenate the Ganga river and its tributaries through pollution control and river conservation efforts. Additionally, the government has invested in wastewater treatment plants and promoted initiatives like Zero Liquid Discharge (ZLD) to reduce industrial pollution. However, the implementation of these measures has been challenging due to high installation costs and management issues.

Overall, urbanisation and industrialisation have been key drivers of river pollution in India, and addressing these issues requires a combination of proper waste management practices, increased investment in infrastructure, and collaborative efforts between communities, industries, and governments.

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