Three occupants of a two-storey building were injured after the roof of the ground floor caved in at Purba Putiari Dakshin Para in Regent Park on Thursday afternoon.
Kolkata Municipal Corporation officials said the 60-year-old building was in a dilapidated state.
Police identified the injured as Sujit Biswas, 62, his wife Basana, 60, and another occupant Tultuli Naskar, 17.
An officer of Regent Park police station said Biswas and Tultuli suffered fractures in waist and legs while Basana was in a “state of shock”.
All three have been admitted to MR Bangur Hospital.
“It appears the owners of the building had failed to detect the condition of the building,” said the councillor of Ward 114, Biswajit Mandal.
“We are going to declare the building dangerous tomorrow (Friday). The building section officials (of the KMC) have visited the spot today. The affected portion of the building will be demolished.”
The cave-in happened around 3pm. “A portion of the concrete roof measuring around 40sqft collapsed on the three,” said the officer.
Neighbours alerted the police and helped in the rescue work.
The area where the incident happened is lined with old buildings.
Several pockets of Kolkata have dilapidated buildings that are dangerous for habitation. The KMC has declared many of them as “dangerous”. But people continue to live in such properties.
A senior officer of the south suburban division said the three occupants had a close shave. “Things could have been worse the way the roof has collapsed,” said the officer.
At least 2,000 buildings have been declared as “unsafe” by the KMC in north and central Kolkata alone. A KMC official said in the past year, portions of at least 1,000 such houses have been demolished.