Kolkata: Paying no heed to directives of the National Green Tribunal, several thousand people forced themselves inside the Rabindra Sarobar on Saturday by breaking open locks of its gates to perform Chhath Puja rituals, officials said.

The NGT, in a directive to the West Bengal government on October 14, had asked it to ensure that there is no violation of an earlier tribunal order, which banned any kind of ritual for Chhath Puja or other festivals in the waters of the Rabindra Sarobar.

An official of the Kolkata Metropolitan Development Authority (KMDA) admitted to the forceful entry of "thousands of people" and said it is looking into the matter.

A police officer guarding one of the gates of the artificial lake said he had tried to reason with the devotees, but they paid no heed to his words.

"We tried to make them understand to not get close to the lake area but in vain. You cannot take any drastic action when there is such a big crowd," the officer said. Around 100 police personnel were deployed outside the gates of Rabindra Sarobar.

When asked about the development by reporters, West Bengal minister Partha Chatterjee said: "This has to be looked nto by the KMDA and Kolkata Municipal Corporation, which had been entrusted with overseeing the security arrangements. I cannot speak on this issue."

Sumita Banerjee, a member of the NGO - Lake Lovers' Forum - said 200 people initially broke open the locks at two gates in the morning and tore notices put up by the KMDA. "As the day progressed, more and more people rushed to the lake area through the other gates. There was little attempt by police to stop them," claimed Banerjee, who had filed a contempt petition after the 2017 NGT order prohibiting Chhath Puja rituals in the lake was flouted.

Vinod Jha, a devotee who came to the lake for the rituals, said, "We have been performing Chhath Puja at Rabindra Sarobar for decades. We will not go to any other place."

Spread over 192 acres, Rabindra Sarovar boasts of rich biodiversity.

Somendra Nath Ghosh, an environmentalist, said the materials used in the puja like vermilion and oil heightens the toxicity levels in the lake.

A KMDA official had earlier said all the 15 gates of the Rabindra Sarobar would be locked on November 2 and till 11 am the following day.

Last year, too, thousands of people got into the lake area for Chhath Puja festivities.