Twelve people died and eleven sustained severe injuries in Coimbatore city when an apartment building collapsed after heavy rain, police said on Saturday.
Three women and a boy were among those who died in the accident late on Friday.
Around 500 policemen were deployed to clear the debris and help with rescue work, city police commissioner CK Gandhirajam said.
The apartments built by the government 30 years ago had developed deep cracks and residents had been advised to move out for repair work.
"The building collapsed even as the victims were still busy packing all that they considered valuable," said a senior police official, who did not wish to be named.
Such accidents are common in India, where houses and flyovers often collapse because of heavy rain, poor construction materials or flouted of building regulations.