Yamuna in Delhi was seen covered with a thick layer of white froth on Friday, with experts saying this poses health hazards for people, especially as the festive season approaches.
Videos circulating on social media show vast sections of the river frothing, resembling clouds over the water, which gradually dissipated later in the day.
The ruling Aam Aadmi Party (AAP) said the city government is closely monitoring the situation.
"Officials have already begun sprinkling defoamers to tackle the issue and the government is actively taking steps to manage and resolve the situation," the party said in a statement.
Bhim Singh Rawat, associate coordinator of the South Asia Network on Dams, Rivers and People (SANDRP), told PTI that normally, the upper segment of the Yamuna experiences significant flood spells, but this year, there was no such spell during the just-concluded southwest monsoon.
"This is unusual as the river generally witnesses at least a couple of low or medium flood spells in this segment every year," Rawat said.
He highlighted that the pollution in the river is a serious concern affecting human health and wildlife.
While the river has some natural cleansing ability, the pollution levels are alarming, Rawat said, adding that the white froth that was seen during monsoon this year becomes more noticeable during festival times.
The AAP said government engineers have been assigned to oversee the operations at the Okhla and Agra Canal barrages. "Monitoring the timings of the barrage gates' opening and providing regular updates to higher authorities," it said.
The engineers have been tasked with uploading photos of the Yamuna downstream at Kalindi Kunj every two hours to ensure continuous observation, it added.
Experts have urged the government to address the pollution levels in the river, especially as major festivals like Chhath Puja are approaching.
The pungent foam contains high levels of ammonia and phosphates, posing serious health risks, including respiratory and skin problems, according to environmental experts.
This kind of foam formation is common when fats from decaying plants and pollutants mix with the water, but its presence during monsoon is surprising, said another expert, attributing the frothing to the absence of flood spells that typically wash away pollutants.
