Fish gasp for oxygen in ‘cleanest’ Yamuna stretch, greens raise a stink

Hundreds of fish died in the Yamuna, and many more were seen gasping for oxygen. The incident happened in the river’s main channel near Burari, between Palla and Wazirabad. This stretch is often considered the cleanest part of the Yamuna in Delhi.

Fishermen first reported a growing stink from the river. Soon afterward, large numbers of dead fish were found floating on Tuesday. The visible deaths suggest a serious change in water conditions, although the exact cause had not been established when the report was published.

The location matters because Burari lies upstream of the Wazirabad barrage. Environmental group Earth Warrior requested immediate investigation and water sampling at upstream sites. Officials were asked to examine pollution sources, including drains and industrial units, and publicly disclose the findings.

The reported scale was substantial but not precisely measured. Visuals showed hundreds of dead fish and many more gasping for oxygen. The article does not provide an exact number, total biomass, or measured length of the affected stretch.

The deaths were found in the Yamuna’s main channel near Burari. This area lies between Palla and Wazirabad and is often regarded as Delhi’s cleanest stretch. Fishermen had noticed a rising stink over several days before large numbers of fish were found floating on Tuesday.

The report does not say that fish died throughout Delhi or along the whole Yamuna. It identifies a specific location, while noting similar events near Burari in May 2025 and July 2024. Authorities still needed to establish whether pollution, low oxygen, toxic substances, or another factor caused the event.

Dissolved oxygen is the oxygen present in water that aquatic animals use for respiration. Fish take it in through their gills. Healthy aquatic systems need enough dissolved oxygen to support fish and other organisms. Measuring it is therefore a direct way to assess whether water can sustain aquatic life.

When pollution or other conditions reduce dissolved oxygen, fish struggle to get enough oxygen from the water. They may move toward the surface and gasp, as fish did in the Yamuna. If oxygen remains too low, fish can become weak, stop functioning normally, and die. This explanation uses established water-science knowledge; the article identifies oxygen testing as necessary but does not confirm the measured level.

Earth Warrior asked for dissolved-oxygen testing at upstream locations. Such results could show whether oxygen depletion contributed to the deaths. They would also help investigators compare conditions near Burari with pollution sources and nearby river sections.

Fish deaths in the Yamuna have often been reported during summer. At that time, reduced river flow can limit the dilution of pollutants. The recent deaths were different because they occurred soon after the monsoon, when the river was expected to have more water and cleaner inflows from upstream.

The location added to the concern. Large numbers of dead fish appeared near Burari, between Palla and Wazirabad. This stretch is often considered the cleanest part of the Yamuna in Delhi. Fishermen had still noticed a rising stink before the deaths, suggesting that water conditions had deteriorated despite the seasonal increase in flow.

The article does not identify the cause. Earth Warrior sought upstream water sampling, while Bhim Singh Rawat called the recurring deaths deeply concerning. Possible contributors mentioned include restricted environmental flows, untreated drain discharges, and industrial pollution. Similar deaths were reported near Burari in May 2025 and July 2024.

Untreated sewage often contains organic material. Microorganisms break it down and use dissolved oxygen in the water. If that demand becomes high, less oxygen remains for fish. Industrial effluent can add chemicals, heavy metals, or other toxic substances that directly harm aquatic life or disrupt its ability to survive.

The article asked investigators to test biochemical oxygen demand and chemical oxygen demand. These measures help indicate how strongly pollutants may consume oxygen or react in water. It also requested tests for faecal coliform, heavy metals, and toxic substances. Together, these tests could distinguish oxygen depletion from direct chemical poisoning, though the article does not report results.

Earth Warrior also urged officials to identify drains and industrial units discharging untreated effluents. Bhim Singh Rawat mentioned untreated discharges and industrial pollution as possible contributors. Real-time monitoring of major drains could help detect recurring pollution and connect it to future fish deaths.

The main concern is the location of the fish deaths. Burari lies upstream of the Wazirabad barrage, and the article describes the area as connected to Delhi’s drinking-water source. Pollution in that section could therefore have implications beyond aquatic life, especially if contaminated water moves toward the barrage.

Bhim Singh Rawat of the South Asia Network on Dams, Rivers and People said that, if pollution caused the deaths, the adverse effect might impact Delhi’s potable water. The article does not provide test results or confirm that drinking water was contaminated. It presents the risk as a reason for urgent investigation.

Earth Warrior requested upstream sampling and public disclosure of the findings. The proposed tests include dissolved oxygen, biochemical and chemical oxygen demand, faecal coliform, heavy metals, and toxic substances. Identifying polluted drains or industrial discharges would help determine whether the water source faces an ongoing threat.

The investigation should examine pollution sources upstream of the fish deaths. Bhim Singh Rawat specifically flagged Drain no. 2 in Panipat and Dhanaura drain in Haryana. Industrial units that may be discharging untreated effluents also need examination. The Delhi Pollution Control Committee, or DPCC, is the authority addressed in the request for action.

Earth Warrior asked for water samples from upstream locations. The proposed tests include dissolved oxygen, biochemical oxygen demand, chemical oxygen demand, faecal coliform, heavy metals, and toxic substances. Investigators were also asked to identify drains or industrial units releasing untreated effluents and to monitor major drains in real time.

These checks could reveal whether oxygen depletion, sewage pollution, industrial toxins, or a combination caused the deaths. The request also calls for public disclosure of results. DPCC’s September analysis had already recorded high pollution at several locations, including elevated biochemical oxygen demand and faecal coliform at ISBT Bridge.