The blaze was reported 3.15 a.m. in the seven-storey Kailash Apartments in Siddharth Nagar of Vikhroli suburb, an official of the Brihanmumbai Municipal Corporation Disaster Control said.
The first flames were noticed on the seventh floor but spread quickly to the sixth and fifth floors, leaving no time for the panicky occupants to escape.
Four members of the Shalivan family, including Gautam (55), his wife Poornima (50), son Vishal (32) and grandson Ayush (10) were burnt to death.
Eight other residents on the lower floors escaped the inferno while firemen rescued the rest. At least two firefighters were also injured during the rescue operations.
Officials said the injured were admitted to the Sion Hospital in Sion and the Rajawadi Hospital in Ghatkopar.
While condition of five injured is reported stable and improving, five others are said to be critical.
According to preliminary investigations, a short-circuit in the electrical wiring in the building's main electrical meter box is believed to have caused the conflagration.
--IANS (Posted on 11-11-2013)