Thousands of fish were found dead in the Yamuna river Monday morning, creating a near panic among fishermen and those living close to the river banks.
Pollution department officials said algae and lack of oxygen probably caused the deaths.
Ashok Kumar Tiwari, regional officer of the UP pollution control board, has sent a team to investigate the fish deaths and suggest remedial measures.
"The Yamuna does not meet any parameters to be called a river anymore. It needs fresh water. Where will it come from? Our materialistic lifestyles need to be modified to one that is nature sustaining and dependent on recycling and re-use," he said.
Fishermen at Poiya Ghat said: "It is dangerous to consume the dead fish."
Environmentalists expressed concern over lack of fresh water in the Yamuna.
"With hardly any water in the river, they have unnecessarily burdened the river with four barrages, the fifth on Palna has been cleared by the Delhi government, without taking into account the capacity of the river," said Ravi Singh, a development scientist.