Section 6(1)(a) in Government Savings Promotion General Rules, 2018
(a)the Aadhaar Number issued by the Unique Identification Authority of India: Provided that where the Aadhaar Number has not been assigned to an individual, he shall furnish proof of application of enrolment for Aadhaar, and if the individual does not submit the proof of application of enrolment, he shall furnish a certified copy of an officially valid document containing details of his identity and address along with a recent photograph.