Indo-Asian News Service said the incident took place at 11:45 p.m. Wednesday when the crane collapsed, sending the slab crashing to the ground.
The injured workers have been sent to two nearby hospitals, officials said.
Workers were part of a construction project on a bridge, which will connect the Chhatrapati Shivaji International Airport to the highway, Indo-Asian News Service said.
This is the third construction emergency on a major infrastructure project in six months, Indo-Asian News Service reported.
Notable deaths of 2014 [PHOTOS]