Four workers suffocated to death while cleaning a water tank at an under-construction building in Mumbai on Sunday, said officials. 

The incident was reported from Bismillah Space building located on Dimtimkar Road in the Nagpada area around 12.30 pm, said officials.

Others at the construction site alerted the fire brigade, which rushed them to the state-run JJ hospital. However, doctors declared them dead, said an official.

Hasipal Shaikh (19), Raja Shaikh (20), Jiaulla Shaikh (36) and Imandu Shaikh (38) were among the dead. 

An accidental death report (ADR) has been registered and a probe has begun to find out lapses, if any, on the part of those who hired the five and whether safety protocols were adhered to, a JJ police station official said.

Officials from the Brihanmumbai Municipal Corporation and local police are at the spot.