Water Pollution In India: Understanding The Main Causes

Water pollution is a pressing issue in India, with around 70% of the country's freshwater sources estimated to be contaminated. The predominant cause is sewage discharge from cities, towns, and villages, which far exceeds the country's sewage treatment capacity. Other factors contributing to water pollution in India include industrial wastewater discharge, agricultural runoff, and population growth, resulting in a severe impact on human health, the environment, and the economy.

Insufficient treatment capacity

India's growing economy and urbanizing landscape have led to an increase in toxic water bodies, with an estimated 70% of surface water unfit for consumption. This is due to the daily discharge of approximately 40 million litres of wastewater into rivers and other water bodies, with only a small fraction adequately treated.

The gap between sewage generation and treatment capacity is a significant issue. Major cities produce 38,354 million litres per day (MLD) of sewage, but the urban sewage treatment capacity is only 11,786 MLD. This results in the discharge of untreated domestic sewage, which is the predominant cause of water pollution in India. The existing sewage treatment plants often don't operate due to improper design, poor maintenance, and a lack of reliable electricity supply. This leads to uncollected waste accumulating in urban areas, causing unhygienic conditions and releasing pollutants that leach into surface and groundwater.

The government has recognized the severity of the issue, with the National Institution for Transforming India (NITI Aayog) reporting that 600 million people in India face extreme to high water stress due to the lack of effective interventions. The growing urban population contributes significantly to water demand and pollution from domestic and industrial wastewater discharges. The Central Pollution Control Board (CPCB) reported that as of 2016, 746 industries were directly depositing wastewater into the Ganga, the largest river in India. This wastewater contains heavy metals and other toxins, severely impacting aquatic life and human health.

To address this, advancements in wastewater treatment technologies are critical. While there have been improvements and cost-effective alternatives are being developed, the lack of infrastructure, funding, and awareness remains a challenge. Reliable data and technology, such as machine learning, are also being leveraged to identify pollution hotspots, predict pollution spread, and inform decision-making to implement effective interventions.

Industrial and agricultural runoff

Agricultural activities, on the other hand, contribute to water pollution through the use of fertilizers, pesticides, and irrigation. These activities lead to the runoff of nitrates, phosphates, and pesticides into nearby water bodies, contaminating water sources and affecting soil fertility. This, in turn, impacts food security and crop yields.

The introduction of agrochemicals, such as HCH and the banned substance DDT, into water bodies is another concerning issue in India. These chemicals are resistant to degradation and can cause bioaccumulation, posing potential health risks as carcinogens and mutagens. Furthermore, India's extensive agricultural practices and expanding population contribute to water scarcity, intensifying the impact of runoff on the environment.

The Central Pollution Control Board (CPCB) reported that, as of 2016, 746 industries were directly depositing wastewater into the Ganga River, which is India's largest. This wastewater contains high levels of heavy metals, including lead, cadmium, copper, chromium, zinc, and arsenic—all of which have detrimental effects on aquatic life and human health.

To address these issues, India has implemented policies and missions under various ministries to achieve efficient wastewater management. The Water (Prevention and Control of Pollution) Act of 1974 establishes standards for the treatment of municipal wastewater by pollution control boards. Additionally, the National Institution for Transforming India (NITI Aayog) has recognized the urgent need for interventions to address the water crisis, with 600 million people in India facing extreme to high water stress.

Population growth and urbanisation

The urban population of Delhi, for example, rose from 53% in 1901 to 97.5% in 2011, with a population increase of 2.1% per year during 2001-2011. This rapid urbanisation has resulted in an upsurge in utility services, leading to overexploitation of groundwater resources. As cities expand, there is a reduction in rainwater infiltration, increased surface runoff and evaporation, and changes in impervious areas, resulting in lower groundwater recharge rates.

Furthermore, the density and volume of the unserved urban population in Indian cities mean that a lack of access to safe water and sanitation services is a significant issue. Unsafe sanitation services and uncollected waste in urban areas cause unhygienic conditions and release pollutants that leach into surface and groundwater. This issue is exacerbated by the fact that India lacks sufficient wastewater treatment capacity, and many existing sewage treatment plants are not operational due to poor maintenance, power supply issues, and absentee employees.

The impact of population growth and urbanisation on water pollution is not limited to India. Studies of the Kelani River in Sri Lanka, for instance, have found a correlation between the growth rate of the population in a watershed area and water quality parameters such as biochemical oxygen demand (BOD), dissolved oxygen (DO), and total coliform (TC). Urban activities, particularly in Asian countries, are a major cause of contamination in surface water bodies.

To address these challenges, India must focus on effective wastewater treatment processes and urban planning that keeps pace with population growth. The New Urban Agenda, adopted by world leaders in 2016, provides a roadmap for building cities that can drive prosperity while also addressing water and sanitation issues.

Poor maintenance of sewage treatment plants

India's water pollution crisis is a complex issue with multiple sources and impacts. One significant contributor is the inadequate maintenance of sewage treatment plants, which play a crucial role in treating domestic wastewater. The problem is not solely a lack of treatment capacity but also the poor operation and maintenance of existing plants.

The majority of government-owned sewage treatment plants in India remain closed most of the time due to various factors, including improper design, poor maintenance, unreliable electricity supply, absentee employees, and inadequate management. These issues highlight systemic challenges that hinder the effective operation of these facilities, ultimately contributing to the water pollution crisis.

Improperly managed sewage treatment plants lead to the discharge of untreated or partially treated sewage into water bodies. This discharge introduces a range of pollutants, such as human waste, chemicals, pharmaceuticals, and pathogens, into rivers and other water sources. Consequently, water pollution poses severe risks to both human health and aquatic ecosystems, causing waterborne diseases and ecological disruptions.

To address this issue, it is essential to prioritize the proper operation and maintenance of sewage treatment plants. This includes ensuring correct plant operation, addressing maintenance issues, improving management practices, and providing reliable electricity. Additionally, investing in decentralized sewage treatment plants and exploring simpler, more cost-effective technologies can help enhance treatment capacity and efficiency.

Furthermore, implementing comprehensive sewage management strategies and adopting sustainable practices can play a pivotal role in mitigating water pollution. This encompasses reducing the use of harmful chemicals, properly disposing of waste, and supporting policies that prioritize clean water for all. By addressing the shortcomings in sewage treatment plant maintenance and adopting a holistic approach to wastewater management, India can make significant strides towards alleviating its water pollution crisis.

Agrochemicals and pesticides

The agricultural industry's extensive use of pesticides and herbicides contributes significantly to water pollution. The rapid population growth and increasing food demand have led to higher pesticide use to boost crop yields. However, the excessive use of these chemicals results in contaminated wastewater, which negatively impacts human health, the ecosystem, and the aquatic environment. India, as a developing country, faces challenges in managing the impact of pesticides on its water resources.

Pesticides, such as Atrazine, Hexazinone, Prometon, Tebuthiuron, and their degradates, have been detected in high concentrations in India's river water, surface water, groundwater, and even rainwater. The presence of these chemicals in water sources poses risks to both human health and the environment. The stability and long half-life of some pesticides, particularly persistent pesticides, prolong the duration of their threat to water bodies.

The introduction of new types of pesticides, such as nano-biopesticides, has raised concerns as well. While these pesticides offer advantages like high selectivity and low toxicity, their small size and high solubility may lead to increased water pollution. Additionally, the use of nanomaterials and genetic engineering in pesticide development adds complexity to understanding their long-term effects on water ecosystems.

To address the issue of agrochemical and pesticide pollution, India needs to invest in wastewater treatment infrastructure and capacity. Properly treating and regulating sewage and agricultural runoff will help reduce the contamination of water sources and mitigate the associated environmental, health, and economic impacts.

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