A 2018 study conducted by the Central Pollution Control Board (CPCB) identified 351 polluted river stretches across India, revealing that untreated wastewater discharge is a primary cause of river pollution. The assessment discovered that rivers and streams in 31 Indian states and Union territories failed to meet water quality standards.
Key Findings of the CPCB Report
The CPCB discovered that nearly 60% of polluted river stretches are in eight states: Maharashtra, Assam, Madhya Pradesh, Kerala, Gujarat, Odisha, West Bengal, and Karnataka. Maharashtra takes the lead, housing the maximum number of polluted river stretches in the country.
Despite the National Green Tribunal instruction’s in 2019 for ensuring 100% sewage treatment by March 2020, the sewage treatment capacity remains disproportionate to the sewage generated in these states.
Disproportionate Sewage Treatment and its Effects
According to the 2021 CPCB report “National inventory of sewage treatment plants,” a whopping 72,368 million litres per day of sewage was generated, compared to an operational treatment capacity of only 26,869 MLD. This untreated or partially treated sewage increases the Biological Oxygen Demand (BOD), thereby polluting the rivers further.
Understanding Biological Oxygen Demand and Dissolved Oxygen
BOD is a measure of the amount of dissolved oxygen required by microorganisms to decompose organic matter in the presence of oxygen. With more organic matter from untreated sewage, the BOD will increase, leaving less oxygen available for higher aquatic life forms, like fish. Therefore, reducing BOD by treating wastewater before its release is crucial to control organic pollution in water bodies.
Dissolved Oxygen (DO) refers to water’s inherent oxygen which is essential for aquatic life. The water quality improves with an increase in DO levels. A DO level of 5 mg/l or above is recommended for river bathing.
Other Causes of River Pollution
Rapid urbanization in India coupled with ill-planned development along river banks has led to an inadequate wastewater management system causing pollution. Other significant factors affecting river purity include the unrestricted flow of industrial and agricultural waste.
Social practices and religious activities, like mass bathing in rivers during festivals and improper cremation rites, also contribute significantly to river pollution.
Government Initiatives to Tackle Water Pollution
Recent government initiatives, like the National Green Tribunal’s directive to the Ministry of Jal Shakti, aim at establishing a national protocol for monitoring measures to curb pollution and rejuvenate polluted river stretches.
Other initiatives include the 2012 National Water Policy, promoting a unified approach towards water conservation and management; the 2010 National Water Mission, focusing on integrated water resource management; and the National Mission for Clean Ganga, aiming to prevent and control pollution in river Ganga.
Potential Solutions to Combat River Pollution
Maintaining a minimum flow in the rivers to support the aquatic ecosystem is necessary. A comprehensive waste management policy emphasizing decentralised garbage disposal practices could incentivize private sector participation.
Bioremediation, the use of microbes for cleaning contaminated soil and water, could be made compulsory in suitable areas. Lastly, encouraging citizen participation to induce behavioural changes is crucial for overhauling the waste management sector.
