CPCB Report on Polluted River Sites

23 Sep 2025

CPCB Report on Polluted River Sites

The Central Pollution Control Board (CPCB) released its 2023 assessment on polluted river sites. 

About the Report

  • The Central Pollution Control Board (CPCB) tracks river health in two-year cycles, focusing on Biological Oxygen Demand (BOD) as the key parameter.
  • The earlier assessment (2022) was based on data from 2019–2021, with 2020 excluded due to the pandemic.
  • The CPCB reviewed water quality data from 2022–2023, covering 2,116 locations.

More on News

  • The report indicates a marginal reduction in polluted river stretches, with some high-priority stretches showing slight improvement.

Key Terms

  • Biological Oxygen Demand (BOD) is the quantity of dissolved oxygen that bacteria require to break down the organic waste in water. It is measured in milligrams of oxygen per liter of water (mg/L).
    • Dissolved Oxygen (DO) is the amount of free oxygen gas present in water available for use by aquatic organisms. It is usually expressed in milligrams of oxygen per liter of water (mg/L).
    • Higher concentrations of waste accelerate decomposition and oxygen use, which in turn lowers the DO content.
  • Polluted River Location:  A Biological Oxygen Demand (BOD) greater than 3 milligrams/litre indicates rising pollution and is considered unfit for bathing.
  • Polluted River Stretch: Two or more consecutive locations, that exceed the BOD criteria, in a single river is counted as a ‘Polluted River Stretch

Key Highlights from the report

  • Polluted River Locations reduced from 815 (2022) to 807 (2023).
  • Polluted River Stretches decreased from 311 (2022) to 296 (2023).
  • State-wise status of PRS:  
    • 2023: Maharashtra (54) > Kerala (31) > Madhya Pradesh & Manipur (18) > Karnataka (14).
    • 2022: Maharashtra (55) > Madhya Pradesh (19) > Bihar (18) > Kerala (18) >  Karnataka (17) > Uttar Pradesh (17)
  • Priority 1 Stretches : 
    • Priority 1 stretches reduced to 37 (2023) from 45 (2022).
    • 2023: Maximum stretches in Tamil Nadu, Uttar Pradesh and Uttarakhand (5)
    • 2022: Maximum stretches in Gujarat and Uttar Pradesh (6)

Priority Categories (BOD-based)

Priority BOD (mg/L) Implication
1 >30 Most polluted, urgent remediation
2 20–30 High pollution, significant intervention needed
3 10–20 Moderate pollution
4 6–10 Low pollution
5 3–6 Least pollution, low intervention

Central Pollution Control Board (CPCB)

  • Formed: It was constituted in September 1974 under the Water Prevention and Control of Pollution Act, 1974.  
  • Powers: It is also entrusted with the powers and functions under the Air (Prevention and Control of Pollution) Act, 1981.
  • Principal Functions: 
    • To promote cleanliness of streams and wells in different areas of the States by prevention, control and abatement of water pollution, and 
    • To improve the quality of air and to prevent, control or abate air pollution in the country.
    • It also provides technical services to the Ministry of Environment and Forests of the provisions of the Environment (Protection) Act, 1986. 
  • Nodal Ministry: Ministry of Environment, Forests and Climate Change
  • Monitoring network: CPCB monitors 4,736 sites across rivers, lakes, creeks, drains, and canals.

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Quick Revise Now !
UDAAN PRELIMS WALLAH
Comprehensive coverage with a concise format
Integration of PYQ within the booklet
Designed as per recent trends of Prelims questions
हिंदी में भी उपलब्ध

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