Ranjeev, a witness, described the moment the flyover fell on top of the vehicles driving underneath.
"The crane was deployed to put up the blocks, suddenly the supporting structure of the crane fell and the people passing underneath were trapped under it. We don't know how many people are there," he said.
Anuj Dayal, an official with the Delhi Metro Rail Corporation (DMRC), announced that a "high level inquiry" had already been launched to identify the cause of the collapse.
As rescue workers continued searching for trapped people, the authorities evacuated the area amid fears other sections of the flyover could give way.
Raj Kumar, director of operations at DMRC, confirmed all building work would now be suspended until a review of the construction programme as a whole and the collapse had been completed.
The families of the two killed in the collapse will receive $673 in compensation while those injured will get $64, according to news agency Reuters.