Aadhaar authentication now governs GST registration timing; failure triggers physical verification or deemed approval deadlines. Applicants (other than persons notified under section 25(6D)) who opt for Aadhaar authentication must undergo authentication on submission; the application date is the Aadhaar authentication date or fifteen days from Part B submission of FORM GST REG 01, whichever is earlier. If Aadhaar authentication is not completed or not opted for, registration requires physical verification of the business premises in the applicant's presence unless a senior officer permits document verification. Prescribed officer time limits for processing applications are set; failure to act within those periods leads to deemed approval. Rule 25 is amended to include not opting for Aadhaar authentication as a verification trigger.