"My fingerprints and iris are mine and my own. The state cannot take away my body," a lawyer told India's Supreme Court last week.
Shyam Divan was arguing a crucial petition challenging a new law that makes it compulsory for people to submit a controversial biometric-based personal identification number while filing income tax returns.
Defending this law, the government's top law officer told the court on Tuesday that an individual's "right to body is not an absolute right".
"You can have right over your body but the state can restrict trading in body organs, so the state can exercise control over the body," Attorney General Mukul Rohatgi said.
At the heart of the latest challenge are rising concerns over the security of this mega biometric database and privacy of the number holders. (The government says it needs to link the identity number to income tax returns to improve compliance and prevent fraud.)
India's biometric database is the world's largest. Over the past eight years, the government has collected fingerprints and iris scans from more than a billion residents - or nearly 90% of the population - and stored them in a high security data centre. In return, each person has been provided with a randomly generated, unique 12-digit identity number.
For a country of 1.2 billion people with only 65 million passport-holders and 200 million with driving licenses, the portable identity number is a boon to the millions who have long suffered for a lack of one.
States have been using the number, also called Aadhaar (Foundation), to transfer government pensions, scholarships, wages for a landmark rural jobs-for-work scheme and benefits for cooking fuel to targeted recipients, and distribute cheap food to the poor.
Over the years, the number has taken a life of its own and begun exerting, what many say, is an overweening and stifling control over people's lives. For many like political scientist Pratap Bhanu Mehta, Aadhaar has transmuted from a "tool of citizen empowerment to a tool of state surveillance and citizen vulnerability".
People will soon need the number to receive benefits from more than 500 of India's 1,200-odd welfare schemes. Even banks and private firms have begun using it to authenticate consumers: a new telecom company snapped up 100 million subscribers in quick time recently by verifying the customer's identity through the number.
People are using the number to even get their marriages registered. The number, says Nikhil Pahwa, editor and publisher of Indian news site MediaNama, is "being forcibly linked to mobile numbers, bank accounts, tax filings, scholarships, pensions, rations, school admissions, health records and much much more, which thus puts more personal information at risk".
Some of the fears are not without basis.
The government has assured that the biometric data is "safe and secure in encrypted form", and anybody found guilty of leaking data can be jailed and fined.
Now a disturbing report by The Centre for Internet and Society claims that details of around 130-135 million Aadhaar numbers, and around 100 million bank numbers of pensioners and rural jobs-for-work beneficiaries have been leaked online by four key government schemes.
More than 230 million people nationwide are accessing welfare benefits using their numbers, and potentially, according to the report, "we could be looking at a data leak closer to that number". And linking the number to different databases - as the government is doing - is increasing the risk of data theft and surveillance.
The chief law officer believes that the outrage over the leaks is "much ado about nothing".
"Biometrics were not leaked, only Aadhaar numbers were leaked. It is nothing substantial. The idea is biometrics should not be leaked," Mukul Rohtagi told the Supreme Court on Tuesday.
The government itself has admitted that it has blacklisted or suspended some 34,000 service providers for helping create "fake" identification numbers or not following proper processes. Two years ago, a man was arrested for getting an identification number for his pet dog. The government itself has deactivated 8.5 million numbers for incorrect data, dodgy biometrics and duplication. Last month, crop loss compensation for more than 40,000 farmers was delayed because their Aadhaar numbers were "entered incorrectly by banks".
There are also concerns that the number can be used for profiling. Recently, authorities asked participants at a function in a restive university campus in southern India to provide their Aadhaar identity numbers. "This is not only a matter of privacy. The all pervasiveness of the Aadhaar number is a threat to freedom of expression, which is a constitutional right," Srinivas Kodali, who investigated the latest report on data leaks, told me.
Critics say the government is steaming ahead with making the number compulsory for a range of services, violating a Supreme Court order which said enrolment would be voluntary. "The main danger of the number," says economist Jean Dreze, "is that it opens the door to mass surveillance."
He says the identity number has cut wastage, removed fakes, curbed corruption and made substantial savings for the government. He insists that the programme is completely encrypted and secure. "It's like you are creating a rule-based society," he told Financial Times recently, "it's the transition that is going on right now."
More than 60 countries around the world take biometric data from its people, says Mr Nilekani. But then there are nagging concerns worldwide about these databases being abused by hackers and state intelligence.
In 2016, personal details of some 50 million people in Turkey were reportedly leaked. (Turkey's population is estimated at 78 million.) In 2015, hackers stole more than five million fingerprints after breaching US government networks. In 2011, French experts discovered a hack involving the theft of millions of people's data in Israel.
Pratap Bhanu Mehta has written that the lack of a "clear transparent consent architecture, no transparent information architecture, no privacy architecture worth the name [India doesn't have a privacy law], and increasingly, no assurance about what exactly you do if the state decides to mess with your identity" could easily make Aadhaar a "tool of state suppression".
So a lot of lingering doubts remain. How pervasive should an identity number be? What about the individual freedom of citizens? How do you ensure the world's biggest biometric database is secure in a country with no privacy laws and a deficient criminal justice system?
In many ways, the debate about Aadhaar is also a debate about the future of India. As lawyer Shyam Divan argued forcefully in the top court, "people are reduced to vassals" when the state controls your body to this extent.