India, May 4 -- A blaze tore through a residential building in east Delhi's Vivek Vihar early on Sunday, killing nine people from three families and critically injuring another, the latest in a series of major infernos in the Capital this year that have raised fresh questions over fire safety in residential buildings.

The fire is suspected to have started after a short-circuit in the outdoor unit of an air-conditioner on the second floor of the four-storey building in B block of Vivek Vihar. Delhi Fire Services officials said the short-circuit likely triggered an explosion, helping the flames spread rapidly and engulf the upper floors.

Rescue personnel from DFS and the Delhi Police said several residents were trapped in by the building'...