The petitioners contend that making Aadhaar mandatory violates the Right to Privacy, which has recently been recognized by the Supreme Court as a fundamental right. The largescale sharing of biometric data like iris scans and finger printing also leaves room for misuse.
The Supreme Court had made Aadhaar voluntary, not compulsory, senior advocate Shyam Dhivan, who was representing the petitioners, told the judges. But a law pushed through parliament last year has given the government power to make it mandatory for accessing any service -- including train and bus travel.
As of now, the Centre demands Aadhaar for 139 schemes, instead of the six schemes cleared by the top court, he said. Aadhaar has been made mandatory for board exams, scholarships and higher education by the education boards and the University Grants Commission. Even HIV-positive patients are denied treatment if they do not have Aadhaar, Mr Dhivan said.
The top court started the hearing as the December 31 deadline for linking Aadhaar banks and financial transactions and welfare measures neared. But two days ago, in a surprise move, the government extended the date of linking Aadhaar to old bank accounts to March 31, 2018.
For accounts opened after 1 June 2017, Aadhaar, Permanent Account Number or PAN will have to be submitted within six months of opening or by 31 March 2018 -- the later date will be the deadline.