A five-judge Constitution bench of the Supreme Court will resume the hearing on the constitutional validity of Aadhaar, the government’s programme to provide a 12-digit biometric-based identity number unique to each citizen, on Thursday.

The petitions primarily question the validity of Aadhaar based on privacy concerns. These also challenge several other aspects of Aadhaar and the sharing of data collected under it, including making it mandatory for social welfare benefits, to file income tax returns, and linking it to mobile numbers and Permanent Account Numbers.

In a landmark ruling in August, the court had declared privacy a fundamental right protected under Article 21 of the Constitution. This was seen as a major blow to the Centre’s push for Aadhaar.

The Constitution bench was initially set up on December 13, but two days later, the Supreme Court agreed to the Centre’s submissions to extend the deadline to link Aadhaar with all government schemes and services to March 31. The interim order also extended the deadline to link Aadhaar with mobile numbers to the end of the financial year.

During the hearing on Wednesday, advocate Shyam Divan, who represents the petitioners, said no democratic society had engaged in a programme of the size and scale of Aadhaar. He claimed that if the Aadhaar programme was allowed to continue unimpeded, it would “hollow out” the Constitution.

The counsel said the government’s unique identity programme was “designed to tether every citizen to an electronic leash”. Divan claimed that the Aadhaar programme “inverts the relationship between the citizen and the state.”

Divan said the petitioners sought a declaration from the court regarding the physical autonomy of the individual, as against the state. Alternatively, they should have the right to opt out of the Aadhaar scheme and have their data destroyed, the counsel said. He added that if the court upheld the Aadhaar Act, no citizen should be deprived of any right or benefit for the lack of an Aadhaar card.

Chief Justice of India Dipak Misra on Wednesday asked lawyers if the decision of the Lok Sabha Speaker to designate a bill as a money bill could be reviewed by the judiciary. The Lok Sabha has the final say in passing a money bill as it has the right to decide on whether to accept or deny amendments proposed by Rajya Sabha.

The question came up when senior counsel Shyam Divan pointed to the amendments made to the Income Tax Act in 2017 through the introduction of the Section 139 AA, which made linking Permanent Account Numbers to Aadhaar mandatory. Divan said the money bill route was used in a manner not intended in the Constitution.