India’s rivers are showing a glimmer of hope! A recent report from the Central Pollution Control Board (CPCB) reveals a slight but significant decrease in the number of river locations considered unsafe for bathing. In 2023, the figure dropped to 807 from 815 in 2022. Even better, there was a noticeable reduction in the number of the most severely polluted sites.
The CPCB meticulously tracks the health of India’s rivers, analyzing data in two-year cycles. Their key indicator is Biological Oxygen Demand (BOD), which acts as a proxy for the amount of organic matter dissolved in the water. A low BOD level signals a healthy river, while anything above 3 milligrams per liter suggests increasing pollution, making the water unsuitable for bathing.
When two consecutive spots along a single river consistently fail to meet water quality standards, they are collectively identified as a ‘polluted river stretch’ (PRS). In 2023, India had 296 such stretches across 271 rivers, a modest improvement from 311 stretches found in 279 rivers in 2022.
Geographically, Maharashtra continues to bear the brunt with the highest number of polluted river stretches at 54, followed by Kerala (31), and then Madhya Pradesh and Manipur with 18 each, and Karnataka (14). Worryingly, Tamil Nadu, Uttar Pradesh, and Uttarakhand each reported the highest number of ‘Priority 1’ stretches – five apiece – indicating the most critical levels of pollution.
For comparison, the 2022 assessment highlighted Gujarat and Uttar Pradesh as having the most ‘Priority 1’ river stretches (6 each). Maharashtra also topped the overall polluted stretches list that year with 55, followed by Madhya Pradesh (19), Bihar (18), Kerala (18), Karnataka (17), and Uttar Pradesh (17).
River stretches are categorized into five ‘Priority’ levels based on their BOD. ‘Priority 1’ signifies the most severely polluted areas, with BOD exceeding 30 mg/L, demanding immediate intervention. ‘Priority 2’ ranges from 20-30 mg/L, down to ‘Priority 5’ with 3-6 mg/L, representing the least polluted but still monitored stretches. The true success of river cleanup initiatives is gauged by how many stretches progress from higher pollution categories (like Priority 1) to lower ones (like Priority 5).
Encouragingly, the latest assessment shows a drop in ‘Priority 1’ stretches from 45 to 37 compared to 2022. Significant improvements were also seen in ‘Priority 4’ (decreasing from 72 to 45) and ‘Priority 5’ (from 175 to 148). The CPCB interprets an increase in ‘Priority 2’ and ‘Priority 3’ stretches as a positive indication, suggesting that more river segments are actively undergoing remediation and moving towards better health.
The CPCB’s comprehensive monitoring network spans an impressive 4,736 locations nationwide, covering not just rivers, but also lakes, creeks, drains, and canals to ensure a broad assessment of water quality.
Looking back to 2018, when the CPCB released its report based on 2016-2017 data, the pollution landscape was different: 45 stretches were in Priority 1, 16 in Priority 2, 43 in Priority 3, 72 in Priority 4, and 175 in Priority 5.
This sustained effort in river remediation gained significant momentum after a 2018 report by The Hindu. Subsequently, the National Green Tribunal (NGT) issued directives mandating the CPCB and the Jal Shakti Ministry to rigorously monitor and address all forms of river pollution. States were specifically instructed to rehabilitate at least one river stretch to a condition suitable for bathing and to develop detailed ‘Action Plans’ outlining their strategies for improving river health.