The number of containment zones in Calcutta went down from 32 to 28 in a fresh list published by the Calcutta Municipal Corporation on Tuesday.

While some pockets have been dropped from the list, a few such as a stretch of Elgin Road and a housing complex on Panditiya Road have been included.

The places that are no longer containment zones include stretches Prannath Pandit Road in Ballygunge, Chakraberia Road in Bhowanipore, Suren Sarkar Road in Phoolbagan, CIT Road Scheme VI in Beleghata and Linton Street in Beniapukur.

The pockets that were declared as containment zones on Tuesday included Ashoka Enclave in Alipore, Rameswara Apartment in Bhowanipore, a housing complex on Alipore’s Burdwan Road, Tower II of Fort Oasis in Panditiya Road and a stretch of Govindapur Road in Jodhpur Park.

A stretch of a road or a lane is turned into a containment zone if at least four cases are reported from a small area in 14 days. If no new case is reported from a containment zone in 14 days, the place is struck off the list.

The CMC has been updating the list of containment zones every two days since July 9. Between May and July, only apartments and standalone houses were sealed if someone tested positive from there and no restrictions were imposed on neighbours.

The new zones include a few houses adjacent to the one where a patient stays or a full tower of a housing complex if someone from a flat in the tower tests positive, but they are smaller in size than the ones declared in May.

In Bidhannagar, the list of containment zones has not undergone any change since it was published on July 9. Sources in the police said the list could be modified soon.

A team of police officers, led by Bidhannagar police commissioner Mukesh, reviewed the containment areas on Tuesday.

“The review found that several places have seen a spike in the number of Covid-19 cases, while no fresh case has been reported from some others,” said an officer. “We have sent our findings to the health department and the Bidhannagar Municipal Corporation.”

The case count has been rising steadily in all 41 wards of the corporation, including pockets in Salt Lake, Baguiati, Kestopur, Kaikhali, Teghoria and parts of Rajarhat.

“We went around the areas from where fresh cases have been reported and those from where no new cases have been reported for a week. We plan to add new containment areas and drop a few from the list,” said Mukesh.