A tortoise carcass and dead fishes were found floating in Rabindra Sarobar in the southern part of the city on Monday, a day after Chhath puja celebrations concluded on its premises, an official said.
Revellers had trooped in the compound of the sarobar (lake) over the past two days to perform Chhath puja rituals, flouting the National Green Tribunal (NGT) order.
The tribunal, in a directive on October 14, had asked the West Bengal government to ensure that there was no violation of its order banning any ritual in the waters of the ecologically sensitive zone.
An official of the Kolkata Metropolitan Development Authority (KMDA) said the tortoise carcass and dead fishes were found floating in the water by morning walkers on Monday.
He, however, clarified that he was not sure if it had anything to do with Chhath festivities.
"The carcass and fish have been sent for lab tests to ascertain the cause of death," the official said.
Environmentalist Somendranath Ghosh maintained that the death of the aquatic creatures were caused by dip in oxygen level in the water.
"The onslaught on the serene, flora-rich lake has destroyed its biodiversity and ecological balance. Our worst fears have come true," Ghosh said.
A team of West Bengal Pollution Control Board has surveyed the spot on Sunday, its chairman Kalyan Rudra said.
"We need to analyse the samples and evidence collected from the site. Only then we can say something," Rudra added.
The sarobar, which is part of the National Lake Conservation Plan of the central government, is home to several species of birds.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)