Number of polluted river sites are showing a slight reduction: CPCB, Pg12

Key Highlights:

• In 2023, 807 locations in Indian rivers were unfit for bathing, a slight decrease from 815 in 2022, according to the CPCB.
• The number of 'most polluted' river locations, termed Priority 1 stretches, decreased from 45 in 2022 to 37 in 2023.
• In 2023, there were 296 polluted river stretches (PRS) identified across 271 rivers.
• Maharashtra had the highest number of PRS with 54 locations, followed by Kerala (31), Madhya Pradesh and Manipur (18 each), and Karnataka (14).

Detailed Insights:

• The CPCB monitors river health by measuring Biological Oxygen Demand (BOD), where a level above 3 mg/L indicates pollution and unsuitability for bathing.
• A polluted river stretch (PRS) is defined as two continuous locations in a single river exceeding the BOD criterion.
• While Maharashtra had the most PRS overall, Tamil Nadu, Uttar Pradesh, and Uttarakhand each had the highest number of stretches in Priority 1, needing immediate attention.
• The CPCB monitors water quality at 4,736 locations nationwide, including rivers, lakes, creeks, drains, and canals.

Key Concepts Involved:

• Biological Oxygen Demand (BOD): The amount of oxygen required by microorganisms to decompose organic matter in water.
• Polluted River Stretch (PRS): Continuous locations in a river exceeding the specified BOD limit, indicating pollution.
• Priority 1 Stretches: River stretches with a BOD exceeding 30 mg/L, classified as the most polluted and requiring urgent remediation.