OC mandatory before the owner can move into their new apartment

Hello, Is OC mandatory before the owner of his / her flat can move into their new apartment? We purchased a flat in a high rise apartment in Bangalore and have been told by the builder that the Occupancy certificate has not yet been received. The keys have been given to us to get the interior work completed. We want to move into our new house ASAP but are not clear if we have to wait for the OC or not? What other documents are needed before we can move into our new apartment? Kind Regards,