NEW DELHI: The UIDAI has directed all telecom operators to enable a facility that will allow subscribers to check the mobile SIMs which are linked to their Aadhaar number, a step to guard against any unauthorised linking.The decision was taken after the UIDAI came to know about some retailers and agents of telecom companies allegedly misusing Aadhaar authentication facility to issue new SIMs or to re-verify mobile numbers other than that of the Aadhaar holder.The Unique Identification Authority of India (UIDAI) has now instructed telcos to ensure that their retailers or agents do not indulge in fraudulent activities related to unauthorised authentication transactions. It also asked the operators to have "sufficient supervision" to avoid any unauthorised authentication transactions.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."The telcos have been asked to provide mechanism, including SMS-based facility that will not only allow their subscribers to check whether their mobile number is linked with Aadhaar but also be informed about other mobile numbers issued or verified against their Aadhaar number.The telecom service providers will provide facility to their subscribers through channels such as customer care number, email, web portal, SMS or app to report any unauthorised mobile number linked with their Aadhaar number.The telecom service providers have been asked to invalidate unauthorised linkings and initiate action in such matters.Sources said that instances had come to UIDAI's notice where multiple successful authentication transactions were being performed under the guise of "failed authentication" and the same was being misused for issuing new mobile SIMs or reverifying subscribers other than the Aadhaar number holder."In light of the above, the telecom service providers are hereby directed to immediately take note of such misuse and curb the malpractices...," the UIDAI said in its recent direction issued to telecom operators.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.Against the 142.9 crore active mobile subscribers, in 85.7 crore cases the mobile connections have already been linked with Aadhaar.