The decision was taken after the UIDAI came to know about some retailers, operators and agents of telecom companies allegedly misusing Aadhaar authentication facility to issue new SIMs or for re-verification of numbers other than that of the Aadhaar holder.

Warning telecom operators to ensure that their retailer and agents do not indulge in any fraudulent activities,  the Unique Identification Authority of India (UIDAI) has directed telcos to make the new facility available to subscribers by March 15.

The telcos have been asked to provide facilities, including SMS-based offering that will allow their subscribers to check whether their mobile number is linked with Aadhaar as well as information on other mobile numbers is issued or verified against that Aadhaar number.

When contacted, UIDAI CEO Ajay Bhushan Pandey told PTI, "In order, for people, to know which mobile number is linked to Aadhaar, all telecom operators have been asked to provide this service to their customers by March 15."

With over 1.2 billion residents already enrolled for the Aadhaar -- the unique 12-digit number backed by fingerprints, iris scans and certain demographic details -- the programme today is the world's largest biometric database. Aadhaar is required as an identity proof of residents by various government and non-government entities.

For instance, the government has made it mandatory for verifying bank accounts and PANs (which helps track tax filings) to weed out black money and bring unaccounted wealth to book.

The same for cellphone SIMs has been mandated to establish the identity of mobile phone users.