"Our control room got information about the accident at 5:21 pm and a fire department team was rushed to the spot for rescue work," an official of the Brihanmumbai Municipal Corporation said.
"The victims had got crushed under the heavy bucket of a JCB machine. They were rushed to the nearby Rajawadi hospital where three of them were declared brought dead, while two others are being treated," the official added.
The labourers were engaged in digging a pit for a sewer line. A private contractor is carrying out the work for the BMC. Those who died are yet to identified.
The injured people have been identified as Ramnath Singh, 48, and Porat Singh, 47. Police said they are investigating how the crane fell and would take action against either the crane driver or the contractor if they were found to be at fault.