All those injured in the collapse have been moved to nearby BDBA hospital.
Mumbai Mirror newspaper quoted a local resident as saying: “I came out after two persons asked us to leave the building.
“As I was rushing out, I saw three buildings, including a dairy, were demolished near our building.”
Mumbai is in monsoon season, typically ending in September. It has historically caused building collapses in India.
Throughout Wednesday heavy rains lashed Mumbai and its suburbs, causing flooding on roads and rail tracks and disrupting suburban train services.
The India Meteorological Department (IMD) issued a ‘red alert’ for Mumbai, and neighbouring Thane, Palghar and Raigad districts, warning of very heavy to extremely heavy rainfall at isolated places there.
The waterlogging caused by the monsoon season’s first rains prompted the traffic police to shut four subways and forced motorists to abandon their vehicles on roads.