Pollution in Indian Rivers: CPCB Report, 2023

Why in the News?

The Central Pollution Control Board (CPCB) released its latest assessment (2022–23) on the health of Indian rivers.

About Central Pollution Control Board (CPCB): 

• Overview: Statutory body set up in September 1974 under the Water (Prevention and Control of Pollution) Act, 1974.
• Expanded mandate: Later entrusted with powers under the Air (Prevention and Control of Pollution) Act, 1981.
• Umbrella role: Serves as the technical arm of the Ministry of Environment, Forest & Climate Change (MoEFCC), implementing provisions of the Environment (Protection) Act, 1986.

• Principal Functions:

1. 1. Water pollution control: Promote cleanliness of streams and wells across states by preventing, controlling, and abating pollution; Oversee the National Water Quality Monitoring Program to collect, collate, and disseminate data.
   2. Air pollution control: Improve air quality and control emissions; Run the National Air Monitoring Programme (NAMP) to determine current status and trends. Regulate industrial pollution, provide baseline data for industrial siting and town planning.
   3. Data Management: Collects, collates, and disseminates technical and statistical data on air and water pollution.

• Key Initiatives and Programs:

  • NAMP: Monitors air quality and pollution trends.
  • NAQI (National Air Quality Index): Offers real-time air quality data.
  • GRAP (Graded Response Action Plan): Measures graded interventions based on severity of pollution.
  • Clean Air Campaign: Awareness and enforcement measures for pollution reduction.

CPCB Assessment of Pollution in Indian Rivers:

Parameters & Definitions:

• Biological Oxygen Demand (BOD): It is the amount of dissolved oxygen needed by microbes to break down organic matter.
  • Healthy river: BOD <3 mg/L.
  • Unfit for bathing: BOD >3 mg/L.
• Polluted River Stretch (PRS): When two or more consecutive locations in a river exceed bathing criteria (BOD >3 mg/L).
• Priority Classification (BOD levels):

1. 1. Priority 1: >30 mg/L → Most polluted, urgent remediation.
   2. Priority 2: 20–30 mg/L.
   3. Priority 3: 10–20 mg/L.
   4. Priority 4: 6–10 mg/L.
   5. Priority 5: 3–6 mg/L → least polluted category but still polluted.

Key Findings of the Report: 

• Unfit bathing locations: 807 (2023) vs 815 (2022), shows marginal dip.
• Polluted River Stretches (PRS): 296 stretches/locations across 271 rivers in 2023 vs 311 stretches in 279 rivers in 2022.
• State-wise PRS (2023):
  1. Maharashtra: 54 (highest).
  2. Kerala: 31.
  3. Madhya Pradesh: 18.
  4. Manipur: 18.
  5. Karnataka: 14.
• Most polluted states by Priority 1 (2023): Tamil Nadu, Uttar Pradesh, Uttarakhand (5 each).
• Most polluted states by Priority 1 (2022): Gujarat and Uttar Pradesh (6 each).

[UPSC 2017] Biological Oxygen Demand (BOD) is a standard criterion for: Options: (a) Measuring oxygen levels in blood (b) Computing oxygen levels in forest ecosystems (c) Pollution assay in aquatic ecosystems * (d) Assessing oxygen levels in high altitude regions