The Central Pollution Control Board (CPCB) has informed the National Green Tribunal (NGT) that, based on statistical analysis, the water quality of the Ganga and Yamuna rivers during the recently concluded Maha Kumbh 2025 in Prayagraj was within permissible limits and fit for bathing.
In a detailed report submitted to the tribunal, the CPCB stated that due to the “variability of data” in water samples collected from different locations and on different dates, individual readings did not necessarily represent the overall river water quality. This necessitated a statistical analysis to derive a more comprehensive assessment, India Today reported.
The report, dated 28 February and uploaded on the NGT’s website on March 7, highlighted that the CPCB conducted bi-weekly water monitoring at multiple locations along the Ganga and Yamuna rivers, beginning from 12 January 2025. Monitoring was particularly focused on auspicious bathing days at five locations along the Ganga and two along the Yamuna.
According to the findings, there was significant variation in water quality parameters, including pH levels, dissolved oxygen (DO), biochemical oxygen demand (BOD), and faecal coliform count (FC). The variability was observed in samples collected from the same location on different dates as well as from different locations on the same day.
The DO level, which indicates oxygen availability in water, was recorded at 8.7 mg/l, significantly surpassing the prescribed norm of 5 mg/l. The BOD level, a key indicator of organic matter decomposition, stood at 2.56 mg/l, well within the permissible limit of ≤3 mg/l. Meanwhile, the median FC count—a crucial measure of sewage contamination—stood at 1,400 units per 100 ml, staying below the permissible threshold of 2,500 units per 100 ml for safe bathing.
The CPCB acknowledged that water quality readings varied due to multiple factors, including anthropogenic activities upstream, river current dynamics, sampling depth, time of collection, and seasonal variations. It emphasised that each sample captured only a snapshot of river conditions at a particular moment, making it difficult to generalize the data for the entire river stretch.
To address these inconsistencies, the CPCB adopted a statistical approach—analysing data from 10 mass bathing locations through 20 rounds of monitoring between January 12 and February 22. The statistical method considered the median value of key parameters rather than individual readings, providing a more reliable assessment of the overall water quality during the Maha Kumbh 2025.
Notably, in an earlier submission dated February 17, the CPCB had reported to the tribunal that several locations in Prayagraj did not meet the primary water quality criteria for bathing due to high faecal coliform levels. However, the latest statistical analysis indicates that, over the entire monitoring period, the overall water quality remained within the required standards for safe bathing.
The NGT is set to hear the matter on April 7, where further discussions on the CPCB’s findings and recommendations are expected.
The Maha Kumbh 2025, which concluded in February, saw millions of devotees taking a dip in the rivers, making water quality a crucial concern. The CPCB’s report provides reassurance that despite temporary fluctuations, the overall water quality during the event remained within the permissible limits for mass bathing.
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