Aadhaar or PAN authentication requirement now mandates quoting and verification in prescribed transactions for tax purposes. Amendments require quoting and authentication of PAN or Aadhaar in prescribed transactions; allow persons without PAN to furnish Aadhaar and obtain PAN; permit persons with PAN who have intimated Aadhaar to quote Aadhaar instead of PAN; replace references to the General Index Register Number with the General Index Register Number or the Aadhaar number; and define Aadhaar number, Assessing Officer (to include PAN allotting authority), and authentication as submission of PAN or Aadhaar with demographic or biometric data for verification by a prescribed authority.