Maharashtra Chief Minister Uddhav Thackeray on Monday took cognisance of the power outage in the Mumbai Metropolitan Region (MMR) and ordered an immediate probe into it.
State Energy Minister Nitin Raut also said the reasons behind the technical snag that caused power failure in parts of the MMR will be probed once the electricity supply is restored.
Mr Thackeray discussed the issue with Raut and asked him to make immediate efforts to restore supply in the MMR.
An official statement said Mr Thackeray took "serious note" of the power outage and ordered an immediate probe into it.
Mr Thackeray also instructed Brihanmumbai Municipal Corporation (BMC) Commissioner Iqbal Singh Chahal to make alternate arrangements so that power supply to hospitals is intact, the statement said.
He also instructed the state Chief Secretary to ensure that the control rooms and fire brigade are alert to see there are no other mishaps due to power outage, it said.
The Chief Minister also asked officials to coordinate with the railway administration to help passengers after the suburban local train services were hit by the power failure, the statement said.
Energy Minister Raut, in a video message and tweets, said the power failure problem is being addressed on a "war-level", and added that it will be restored in approximately an hour.
"Once the power is restored, a probe will be carried out into reasons which led to the technical snag," he tweeted.
Train services came to a halt in Mumbai in the morning as a grid failure resulted in massive power outages across the city.
The exact reason for the failure was not immediately known, but the Western Railway and the Brihanmumbai Electric Supply and Transport (BEST), the state-run discom supplying power to the island city, blamed the fault on Tata Power.