Thane: Thirty seven-year-old Imran Siddiqui lies in a hospital bed with multiple fractures.

There is the unbearable pain of having lost 12 family members, including his wife, who was eight months pregnant, when the building they lived in near Mumbai collapsed on Thursday evening.

"I have lost everyone. Please do something to help me," said Mr Siddiqui. Both his legs are broken.At least 40 people have died in the disaster. Among them were 11 children. Fifty people have been injured and on Friday evening, 20 were still missing in the mound of debris that was being tackled by rescue workers armed with sledgehammers, gasoline-powered saws and hydraulic jacks.

At the time of the collapse, between 100 and 150 people were in the building. Many were residents or construction workers, who were living at the site as they worked on it, said Sandeep Malvi, a spokesman for the Thane government.

At least four floors of the building had been completed and were occupied. Workers had finished three more floors and were adding the eighth when it collapsed, police Inspector Digamber Jangale said.

It was not immediately clear what caused the structure to collapse, but officials said it had been built in just two months, with sub-standard material, and without any clearances.

The police is searching for the builders to arrest them.