A government-commissioned scientific study has revealed alarming inconsistencies in the official water quality data for the Yamuna river, casting doubt on the monitoring mechanisms of the Delhi Jal Board (DJB) and raising urgent questions about public safety.
Stark Contrast in Ammonia Readings
The report, prepared by The Energy and Resources Institute (TERI) and accepted by the Delhi government, was made public in December 2025. It presents findings from samples collected on December 17, 2024—a month when the capital faced a severe ammonia crisis. The TERI study recorded ammonia concentrations of 27.4 mg/l upstream of the Wazirabad barrage and an even higher 30.6 mg/l downstream, taken before the confluence with the Najafgarh drain.
In sharp contrast, the DJB's official data for the same period and location claimed the ammonia level was a maximum of only 5 mg/l upstream of Wazirabad. This gap is critically significant because water with ammonia levels beyond 0.95 to 1 mg/l is considered untreatable for drinking purposes, directly threatening Delhi's potable water supply.
Questions Over Monitoring and Transparency
The discrepancies are not isolated to a single event. The TERI report documented consistently high ammonia levels both before and after the monsoon in 2024 and 2025 at various sewage treatment plants and drains, findings that diverge sharply from official claims. This variance has sparked serious speculation:
- Is the DJB's water testing and monitoring mechanism reliable?
- How does the Board explain such a wide difference with a government-approved scientific study?
- Why is this critical water quality data not routinely made available to the public?
Activist Pankaj Kumar of Earth Warrior highlighted the transparency issue, noting that parameters for drinking water supplied by DJB are not publicly accessible and must be sought through Right to Information (RTI) requests. "The TERI report raises a lot of questions... Were the people of Delhi being supplied contaminated water? Why is the data not public?" he asked.
DJB's Response and Explanations
DJB officials did not outright refute the high ammonia levels indicated by the TERI study. One official acknowledged the problem, attributing it to industrial pollution from neighbouring areas. "Drain DD6 carries industrial effluents from Panipat... Panipat often flushes its effluents at night. The dirty wastewater spills over or enters other drains through leakages. So ammonia levels are often quite high in the river; we don't refute it," the official stated, adding that levels sometimes reach 50 ppm. In such scenarios, the DJB flushes the contaminated water forward and sources water for drinking from the Haiderpur drain.
Another official pointed to methodological differences, arguing that the TERI and DJB sample collection locations may not be identical. The official explained that DJB dilutes the ammonia-laden raw water from upstream of Wazirabad by mixing it with a huge quantity of ammonia-free water from the Carrier Lined Channel (CLC) near Haiderpur. "To compare the levels, the locations of TERI water collections must be the same as DJB's," the official contended.
This investigation, based on the TERI findings, underscores a pressing need for independent verification, greater transparency, and robust action to safeguard the Yamuna and ensure the millions relying on it for drinking water are not at risk.
