The bus, which was on its way to Borivali had 35 passengers on board and was coming from Devrukh town in Maharashtra's Ratangiri district when its driver lost control of the vehicle. The accident happened at around 5 am.
The bus hit a road-divider on Dadar TT bridge and then toppled, Matunga police station's Senior Inspector BM Kakad said.
One of the passengers, Sainath Bahalekar (35), died in the accident while the 34 injured passengers were taken to a hospital nearby, he said. The accident briefly led to traffic disruption on the bridge. The bus was later removed from the spot and the traffic movement was restored, Mr Kakad said.
Police have arrested the bus driver, Muttu Nadar, who was also injured in the accident, he said.
Mr Kakad said it does not appear that the driver was in an inebriated state but his blood samples have been taken for further examination. A case has been registered against the driver on the charge of causing death by negligence, rash driving and endangering life or personal safety of others, he said.