The Central Pollution Control Board (CPCB) has released its latest assessment of river water quality, based on data from 2022 and 2023, revealing a significant reduction in the total number of identified Polluted River Stretches (PRS) across the country. This improvement is attributed to concerted efforts by State Governments toward better infrastructure for sewage, industrial effluent, and waste management.
The CPCB executes the National Water Quality Monitoring Programme (NWMP), currently monitoring water quality at 4,736 locations, including 2,155 locations on rivers. The assessment uses Bio-Chemical Oxygen Demand (BOD) as the key criterion parameter for identifying polluted areas needing restoration and targeted action plans. The primary compliance standard is a BOD value of less than 3.0 mg/L, which is the criteria for Outdoor Bathing.
Key Findings of the 2025 Assessment
The latest assessment, based on water quality data from 2022 and 2023, shows a positive national trend:
- Overall Reduction in PRS: The total number of identified PRS has decreased from 351 in 2018 to 296 in 2025.
- Compliance: Out of 2,116 river locations monitored in 2022-2023, 1,299 locations (62%) were complying with the BOD criteria of less than 3.0 mg/L.
- Historical Context: The proportion of monitored rivers identified as polluted has seen a major drop over the past decade:
- 2015: 70% of rivers monitored (275 out of 390) were polluted.
- 2022: Only 46% of rivers monitored (279 out of 603) were polluted.
| Assessment Year | Monitoring Period | Total Polluted Stretches Identified | Total Rivers Identified as Polluted |
| 2009 | 2002 – 2008 | 150 | 121 |
| 2015 | 2009 – 2012 | 302 | 275 |
| 2018 | 2016 – 2017 | 351 | 323 |
| 2025 | 2022 – 2023 | 296 | N/A |
Observed Improvements in Polluted River Stretches
Detailed analysis comparing the current findings with the 2018 assessment highlights significant improvement across 220 previously identified PRS:
- 149 Stretches No Longer Polluted: These river stretches are no longer identified as polluted due to compliance with the BOD criterion (value less than 3.0 mg/L). States with the most significant number of delisted stretches include Assam (41), Odisha (14), Madhya Pradesh (11), and Goa (10).
- 71 Stretches Downgraded in Priority: The water quality improved enough in 71 other stretches to shift their priority classification to a lower, less critical class. Maharashtra (29) accounted for the highest number of such improvements.
- Highest Priority Improvements: The assessment specifically notes a substantial reduction in the number of PRS in Priority I, IV, and V.
Stretches Showing No Improvement
Despite the overall positive trend, the water quality of 85 polluted river stretches identified in both the 2018 and 2025 assessments remained unchanged. These stretches show no improvement and their priority classes remained the same, demanding urgent and continued intervention.
Out of these 85 critical stretches:
- 25 are classified under Priority I (P-I).
- 46 are classified under Priority V (P-V).