Idols of Goddess Lakshmi will have to be immersed in designated ponds in Lake Town, Dum Dum, New Town, and Behala, the police commissionerates of Calcutta and Bidhannagar have been instructed.

In a communique to the commissionerates on Friday, Bhabani Bhawan, the Bengal police headquarters, asked officers to strictly monitor that immersions were carried out in the designated ponds.

The state pollution control board has identified two ponds, Debi ghat in Lake Town and Pond No. 4 in Dum Dum Park, for immersion of Lakshmi idols in accordance with the National Mission for Clean Ganga guidelines.

Both these ponds, along with Upsana ghat in New Town, earmarked by the New Town Kolkata Development Authority, is in the Bidhannagar commissionerate’s jurisdiction. The one in Behala, earmarked by the Calcutta Municipal Corporation, is in the city police’s jurisdiction.

A joint team of officers from the commissionerates and officials from the state pollution control board will oversee the immersion before water samples are collected to test water quality after immersion.

The police have been told about the ponds, Rajesh Kumar, member secretary of the state pollution control board, said. “The board has created facilities to help organisers with the immersions.”

Most home Lakshmi idols will be immersed on Saturday. Some puja committees have told the police that idols would be immersed on Sunday.

“We want all Lakshmi idols, including those from homes in these parts of the city, to be immersed in the designated ponds. This is the first time we are trying this out and we want to see how it works,” Kalyan Rudra, chairman of the state pollution control board, said.

The designated ponds have been fitted with synthetic linings to arrest pollutants that get dissolved in the water, the police said.

The pollution control board immersion action followed a meeting chaired by chief secretary Alapan Bandyopadhyay on October 17 where the importance of following the NMCG guidelines had been stressed in the presence of Rudra and Rajesh Kumar.

The NMCG, which had issued the guidelines in 2018, recently reiterated that they be followed.