A lawyer is urging people to boycott the world's largest biometric database, which is being introduced across India.
The controversial programme aims to scan the eyes and take the fingerprints of most of the population over the next decade.
Each person will then be given a 12-digit number. They will be able to use the number - which serves as a key to their biometric data - to prove their identity and access India's sprawling welfare state.
But Supreme Court lawyer and human rights activist, Sanjay Barikh, says the scheme is an invasion of privacy.
He is urging citizens not to take part, claiming it will lead to unnecessary state intrusion.
"When they get the information then all the time that person will be under some kind of surveillance and it is questionable whether that information will be kept secret or whether it will be passed on to other countries and companies as well," he said.
The scheme is already well underway and more than one million people being processed every day.
The authorities claim the biometric identity project - which is called Aadhaar (foundation) - is vital if India is to eradicate poverty and beat corruption...