Recent data from the Central Pollution Control Board (CPCB) reveals a modest decline in the number of Indian river locations unfit for bathing. The 2023 report shows 807 such locations compared to 815 in 2022. The report also notes a decrease in the most polluted river stretches, signalling some progress in river health management.
About River Pollution Monitoring
The CPCB monitors river health every two years. It uses Biological Oxygen Demand (BOD) as the key parameter. BOD measures the amount of organic matter in water. A BOD above 3 milligrams per litre indicates pollution levels unsafe for bathing. This helps identify polluted river stretches (PRS), defined as two or more consecutive locations in a river exceeding the BOD limit.
Polluted River Stretches in 2023
In 2023, 296 PRS were detected across 271 rivers. This is a decrease from 311 PRS in 279 rivers in 2022. Maharashtra leads with 54 polluted stretches, followed by Kerala (31), Madhya Pradesh and Manipur (18 each), and Karnataka (14). Tamil Nadu, Uttar Pradesh, and Uttarakhand had the highest number of Priority 1 stretches, with five each.
Priority 1 River Stretches
Priority 1 stretches have BOD levels exceeding 30 mg per litre, marking them as the most polluted and in urgent need of cleaning. The number of Priority 1 stretches dropped from 45 in 2022 to 37 in 2023. States like Tamil Nadu, Uttar Pradesh, and Uttarakhand now have the highest count of these critical stretches. In 2022, Gujarat and Uttar Pradesh had the highest number of Priority 1 locations.
CPCB’s Monitoring Network and Scope
The CPCB tracks water quality at 4,736 locations nationwide. These include rivers, lakes, creeks, drains, and canals. Continuous monitoring supports targeted efforts to improve water quality and public health. The data helps policymakers and environmentalists prioritise river restoration projects.
Significance of BOD in River Health
BOD reflects the amount of oxygen needed by microorganisms to decompose organic matter. Low BOD values indicate cleaner water with less organic pollution. High BOD reduces oxygen available for aquatic life. Thus, BOD is a critical indicator of river ecosystem health and suitability for human use.
State-wise Pollution Trends
Maharashtra remains the state with the highest number of polluted stretches. However, the reduction in overall PRS and Priority 1 stretches indicates some success in pollution control efforts. States like Kerala and Madhya Pradesh also show notable pollution levels. The data suggests a need for sustained and enhanced pollution control measures nationwide.
Questions for UPSC:
- Critically discuss the role of Biological Oxygen Demand (BOD) as an indicator of water quality in Indian rivers. With suitable examples, explain its impact on aquatic ecosystems and human health.
- Examine the challenges and policy measures for controlling river pollution in India. How effective have recent initiatives been in improving river water quality?
- Discuss in the light of India’s river pollution data, the importance of state-level governance and community participation in water resource management.
- Analyse the impact of industrialisation and urbanisation on river pollution in India. Taking examples from major polluted rivers, suggest sustainable solutions to mitigate this problem.
