Rescuers in India's financial capital are still sifting rubble today in a desperate search for survivors of the collapse of an 117-year-old condemned building, as the toll from the disaster rose to 33, Reuters has reported this morning.

The agency said that there was no reliable estimate of those still missing in what is the second such collapse in a little over a month, which came as Mumbai recovered from two days of floods brought by heavy monsoon rains.

A total of 46 people have been pulled from the rubble since the collapse of the building early on Thursday morning, 33 of whom have been declared dead, Reuters quoted the the chief fire official as saying.

"Rescue operations are continuing," said P.S. Rahangdale, adding that 14 fire and rescue officials had been injured in the effort. "Fire engines, rescue vans and ambulances are still at the site."

Police have yet to determine what caused the crumbling of the building in a densely-populated area of the city, many of whose residents had stayed on even after authorities declared it unsafe in 2011.

According to the Reuters report, people had been reluctant to leave because they had not received details of alternative housing.