A house on Rowland Road in Ballygunge, some apartments in a building near Ballygunge Phari and some flats in another building in Ekbalpore were declared as Covid containment zones on Monday.
Following the additions, there are now five containment zones in the city.
Six residents of the Rowland Road house and nine residents of the building near Ballygunge Phari have tested positive for Covid-19, said Asim Bose, coordinator of Ward 70.
It was not immediately clear how many residents of the other building have tested positive.
“We are only asking residents of the flat where someone has tested positive to stay isolated. People who have come in contact with an infected person are also being said so. But not others,” said Bose.
“Suppose someone lives on the eighth floor and has not come in contact with an infected person on the fourth floor, that person is free to follow his or her normal routine,” Bose said.
A civic official said a flat or a road or a house is declared as a containment zone only when several people test positive from a small area within a few days.
“If a small road has four or five positive cases, it can be declared as a containment zone. But if five persons test positive on a long road, with people staying far from each other, there is no need to declare the road as a containment zone,” said the CMC official.