Legal challenges to the Indian government's ambitious biometric ID programme spurred the country's Supreme Court on Wednesday to debate whether privacy was a fundamental right under the constitution.
Several petitions before the court question the legal basis of the Unique Identification project, which aims to provide every resident with a number linked to a database with records of personal details and biometric data.
The 22 petitions joined together by the Supreme Court challenge the project on various grounds, including infringement of the right to privacy, the use and sharing of the data collected, and the government making participation mandatory in order to receive welfare benefits.
"But first the court has to decide whether the right to privacy is a fundamental right," said lawyer and rights activist Prashant Bhushan, who is representing one of the petitioners.
Lawyers for the government said the right to privacy was not a fundamental right because it was not in the constitution.
But according to the petitioners, the right to privacy is a "pre-existing natural right which is inherent in the constitution though not explicitly mentioned," lawyer Gopal Subramaniam was quoted as saying by IANS news agency. 
"How do we define privacy? ... What obligations does the State have to protect a person's privacy?" one of the judges, DY Chandrachud, said during Wednesday's hearing, according to the Hindu newspaper.
Several members of bench expressed the opinion that the right to privacy was not an absolute right and the state could not be prevented from making laws that imposed reasonable restrictions on its citizens. 
Earlier decisions of the court in 1954 and in 1962 had held that privacy was not a fundamental right.
Once a nine-judge bench decided on the privacy issue, a smaller bench would take up issues raised in the petitions.
The bench was scheduled to continue its hearing on the subject on Thursday.