NEW DELHI: India’s top court yesterday began hearing a challenge to the legality of a government identity scheme that holds biometric data on more than a billion people, reports AFP.

The “Aadhaar” system uses fingerprints and iris scans to provide users a 12-digit unique identity number they can use to access government and other services.

It was intended as a voluntary programme to reduce official corruption in the payment of subsidies and other aid programmes.

But critics say its growing use for everything from banking to mobile phone contracts has effectively made it compulsory, violating citizens’ right to privacy.

Numerous challenges to the scheme have come before India’s Supreme Court, which said last year it would set up a special panel to rule on the legality of the scheme.

It follows a landmark ruling by the court last year recognising privacy as a fundamental right. In their introduction to the court on Wednesday, a host of petitioners led by ex-army officer S.G. Vombatkere, social activists Bezwada Wilson and Kalyani Menon Sen challenged the scheme saying it was “reminiscent of totalitarian regimes”.

“Every basic facility is linked to Aadhaar and one cannot live in society without an Aadhaar number,” they said.

Launched in 2009, Aadhaar was meant to operate as a voluntary scheme that would provide identity cards to millions of poor people to make welfare payments easier and curb wastage in public spending.