Aadhaar authentication for GST registration required from specified date; alternate viable identification permitted if Aadhaar unavailable Notification requires individuals to undergo Aadhaar authentication of their Aadhaar number to be eligible for GST registration under the registration rules; where Aadhaar is not assigned, the individual shall be offered alternate and viable means of identification as specified in the registration rules. The notification fixes the date from which this authentication requirement and the alternate identification procedure shall operate.