The car driver Pravin Kanojia (25) was caught by passersby and was later arrested, police said.
The deceased were identified as Sangeeta Vanaj (22) and Rekha Padhonale (22), while the injured are: Manju Prabhakaran (30), Sneha Wadekar (25), Ragini Maniprakash (19) and Anupriya Muttu (20).
The incident took place at about 7 am on Jogeshwari Vikhroli Link Road (JVLR) in Seepz, police said, adding, the South-bound Indica car was speeding on the road when the women, working in the area, were crossing the road.
"The accused claimed that the six persons suddenly appeared from behind a BEST bus halted on the JVLR Road while he was driving the vehicle at full speed," said Uttam More, senior inspector at Aarey Sub Police Station.
By the time the driver applied the brakes, it was too late, and all the six were hit by the car.
They were rushed to the nearby Holy Spirit Hospital, police said, adding, Vanaj and Padhonale declared brought dead while four others were undergoing treatment.
Prabhakaran and Wadekar are in ICU, police said, adding, the two others are out of danger.