Recent official data indicates the Yamuna river's health showed some improvement during the final months of 2025 compared to the previous year. However, environmental experts and activists are raising serious concerns about apparent inconsistencies in the numbers, suggesting the official picture may not fully reflect the grim reality on the ground.
Official Data Shows Year-on-Year Improvement
The Delhi Pollution Control Committee (DPCC) released a water quality report this Sunday covering the period of November and December 2025. The data points to a better situation in the river compared to the same months in 2024.
In terms of faecal coliform, which indicates the presence of untreated sewage, the levels were significantly lower. At the ISBT bridge, a critical point just after the Najafgarh drain meets the Yamuna, the count was 20,000 MPN/100 ml in November and 92,000 in December 2025. This is a stark contrast to December 2024, when the faecal coliform peaked at a staggering 8.4 million units. However, both the 2025 figures remain far above the safe limit of 2,500 MPN/100 ml and the desired level of under 500.
A similar trend was observed in Biochemical Oxygen Demand (BOD), a key measure of organic pollution. The BOD peaked at 33 mg/l in November 2025 and came down to 25 mg/l in December. While this is eight times the safe limit of 3 mg/l, it is a notable improvement from the peak of 70 mg/l recorded in December 2024.
Experts Flag Inconsistencies in the Numbers
Despite the reported year-on-year improvement, several experts have pointed out anomalies that, in their view, make the data difficult to reconcile with observable conditions.
A major point of contention is the comparison with October 2025. During the Chhath Puja festival, the river underwent a significant cleaning operation. An excessive flow of water was released from upstream barrages, which temporarily reduced frothing and improved the river's appearance. Yet, the DPCC data shows that at some locations, pollution parameters were worse in October than in the following months when the stench and froth had visibly returned.
Pankaj Kumar from the environmental group Lone Earth Warrior provided a detailed analysis. "At Kalindi Kunj, the BOD in November was 14mg/l and 17 mg/l in December. Dissolved oxygen was over 2mg/l in both months," he noted. "If we compare this with the sample taken on October 20, 2025, when fresh water flow was much higher, the BOD was 20mg/l and DO was 1mg/l. This raises doubts."
He questioned how the river could show worse BOD during a period of high flow and visual cleanliness compared to months marked by renewed frothing and foul smell.
Drain Data Versus River Quality: A Mismatch
Further skepticism arises from a mismatch between the pollution levels in major drains and the Yamuna's water quality at their confluence points.
Kumar highlighted that in November and December, around six to seven major drains had extremely high BOD levels, exceeding 100 mg/l. Despite this heavy pollution load entering the river, the DPCC report indicated improved water quality at certain downstream stretches like the Okhla Barrage.
For instance, the Najafgarh drain had a BOD of 34 mg/l and 42 mg/l in November and December respectively. Other drains like Sen’s Nursing, Tughlakabad, Maharani, and Shahdara were reportedly "much worse." Logically, this should increase the river's pollution load downstream. However, the BOD at the Okhla Barrage showed improvement, reading 14 mg/l in November and 17 mg/l in December, compared to 20 mg/l in October.
"This makes little sense. If downstream drains are more polluted, then the pollution load of the river must increase, but it is not happening in the reports," Kumar asserted.
The Times of India sent queries to the nodal officer at DPCC seeking clarification on these discrepancies but did not receive a reply. The lack of official explanation leaves the questions raised by environmental watchdogs unanswered, casting a shadow over the reported improvements in the Yamuna's health.
