Fortis Healthcare said it would commence coronavirus vaccination for adults at all its centres in north India from Saturday, while the drive would start in other cities as soon as supplies were made available by the authorities.Apart from Fortis, Apollo Hospitals will also begin the third phase of the inoculation drive after the Centre opened up vaccination for all adults.”Fortis will administer COVID vaccines for 18+ at its centres across North India from tomorrow,” according to a statement on Friday.”Fortis centres in other cities will commence vaccination as soon as supplies are made available by the authorities,” a statement said.