At least 39 people were killed and dozens injured after an illegal, half-constructed building collapsed in seconds "like a pack of cards" on the outskirts of India's financial centre Mumbai, officials and witnesses said.
Rescue workers using cranes and bulldozers searched for survivors in the wreck of steel and concrete on Friday after the seven-storey building crumbled on Thursday night. Residents said labourers paying rent of around $5 a day had lived in it.
A shortage of cheap homes in Asia's third-largest economy has led to a rise in illegal construction by developers who use substandard materials and shoddy methods in order to offer rock-bottom rents to low-paid workers.
"The building collapsed like a pack of cards within three to four seconds," said Ramlal, a local resident. "It just tilted a bit and collapsed," he said.
The building, which was in a forested area in the city of Thane, had been made using poor materials and without proper approvals, said Sandeep Malvi, a spokesman for licencing authority the Thane Municipal Corporation.
He said 39 people had been killed and 69 injured. Indian media quoted officials giving higher death tolls.
Rescue workers pulled an infant alive from the rubble as they used jackhammers and other equipment to cut through metal and concrete in their hunt for survivors.
Police said they were searching for the builders and would charge them with culpable homicide in connection with the disaster.
"Unauthorised constructions are a product of unavailability of affordable housing," said Lalit Kumar Jain, president of the Confederation of Real Estate Developers of India.
A sharp rise in property prices in densely populated Mumbai over the past five years has put housing out of reach for tens of thousands of lower earners, many of whom moved to the city in search of jobs, and who now sleep on the streets or in slums.
In 2012, India's urban housing shortage was estimated at nearly 19 million households, according to a report by the Ministry of Housing and Urban Poverty Alleviation.