Forty-three people have been killed so far after an 11-storey building in Chennai collapsed on Saturday.
Officials say 27 have been pulled out alive while two more could still be inside.
Workers continue to drill holes and clear the rubble from the site, where faint cries for help could be heard till Monday.
Most of those in the building when it collapsed were construction workers from Andhra Pradesh and the northern states. Many were in the building to collect their wages.
“Clearing the debris is a huge challenge. We hope to save more lives,” a senior cop said.
On Sunday, Tamil Nadu Chief Minister J Jayalalithaa said there were 72 construction workers in the building when it collapsed. She said the building appeared to have serious structural defects and had not adhered to the approved plans.
Five people, including the promoters and engineers of the building, have been arrested and charged with violations.
A National Disaster Response Force team has been leading rescue work using gas cutters, iron rods and shovels after cranes lifted concrete blocks to get to the survivors.
On Saturday, 11 people died in Delhi when a 50-year-old four-storey building collapsed.
In April last year, 74 people were killed when an eight-storey building being constructed illegally in the Mumbai suburb of Thane in western Maharashtra had collapsed.