Ten people died after the portion of an unauthorised three-storeyed building in Kalwa collapsed on Tuesday evening.
This is the third building crash in Kalwa this year. In the earlier two incidents, no deaths had taken place as residents had been evacuated in time.
The left portion of Sonibai Bhawan, built 27 years ago in the Gaondevi area, crashed at around 4.30 pm. Of the 21 families staying in the building, nine are in this part.
While residents of the other part of the building were evacuated by civic officials, 14 people were trapped under the debris. Ten of them died. The four who were injured were admitted to the Chhatrapati Shivaji Maharaj Hospital.
Civic commissioner R.A. Rajeev said: "We had asked residents to vacate this building. Most Kalwa buildings are unauthorised. Redevelopment of these buildings is the only solution."
Deputy municipal commissioner (anti-encroachment), B.G. Pawar, said Tuesday's tremors in Thane may have led to the crash.
"The building was very old, but it was not in our list of dilapidated structures," he said.
None of the three buildings that crashed this year have been dilapidated structures.
Rajeev said compensation would be paid in accordance with state policy.