Indian activists are challenging Prime Minister Narendra Modi's government over the use of AI-powered surveillance used at the largest youth protest in decades, with one court case set ‌to become a test of federal powers even after agitation ended.

The surveillance controversy erupted during last week's student protest over exam paper leaks, when demonstrators posted pictures on social media of a mobile police surveillance van equipped with cameras on a telescopic mast providing a 360-degree view of the gathering.

One protester, student activist Aishe Ghosh, has asked the Delhi High Court to declare mass surveillance of protesters unconstitutional and direct the destruction of all personal data collected during the demonstration, as well as order the framing of guidelines on how surveillance technology can be used.

Ghosh is pressing on with the case even though the protest ended after Education Minister Dharmendra Pradhan resigned in a rare ⁠setback for Modi, who has since announced a panel to overhaul the cheating-prone exam system.

India has no law governing the use of facial recognition technology by police and surveillance at the main protest site in New Delhi was a breach of the law, activists say.

The government says such checks were legal and in the public interest to ensure law and order.

Modi's government has often been accused by opposition parties and digital rights advocates of expanding surveillance powers and tightly controlling digital communications. It has rejected such accusations, saying it only acts in the public interest.

During a hearing on Friday, Solicitor General Tushar Mehta defended the Indian police conduct, saying privacy claims at a public gathering were "ironical" and the checks were "absolutely necessary" and "in legitimate state interest."

In a brief hearing on Monday, judges heard arguments from Ghosh that intrusive mass surveillance of protesters was disproportionate, as she sought broader disclosures on the state's surveillance policies during protests. The court will hear the matter on Tuesday.

'NEED FOR ACCOUNTABILITY'

Internet Freedom Foundation, a New Delhi-based digital advocacy group, wrote to Delhi's police commissioner on July 24 demanding the deletion of ‌biometric data ⁠collected at the protest site.

Delhi police did not respond to a Reuters request for comment. In a post on social media platform X on Sunday, the force said it had not "restricted anyone's freedom through the use of facial recognition technology".

"We need proportionality even if we are to claim national security risks. Accountability must flow both ways," said Akash Karmakar, a technology law partner at Indian law firm Panag & Babu.

He said if India used facial recognition to track protesters, it must also be used to identify police officers who allegedly acted without name badges during the crackdown.

Police were also seen noting Instagram ⁠handles of protesters arriving at the site. Inspector Sunil Kumar told Reuters the checks were to ensure no one with a criminal background entered the protest.

'FACE ACCURACY' MATCH

The surveillance van parked at the site was emblazoned with the Delhi Police crest and the branding "Ikshana", Hindi for "vision".

There is little detail online about Ikshana, barring one post from its development partner, Indian CCTV company CP Plus, which said they were ⁠equipped with "Advanced AI-powered" cameras, mobile cameras and "Varifocal Bullet Cameras" with adjustable lenses.

That 2023 post on CP Plus' website was removed at the weekend. CP Plus said in a statement that it supplied the surveillance hardware that forms part of the security infrastructure deployed by Delhi Police but the operational use, databases and deployment scenarios were designed and deployed by the law ⁠enforcement authority.

When a Reuters reporter walked past the van last week, one computer display inside showed his face with a green rectangular box around it and a "face accuracy" match metric next to it. Soon after, a police officer inside shut the van's window.

"The computers here help us identify those who have a criminal history and it highlights them," police officer Raj Kumar Dahiya told Reuters.

"AI also helps us count the number of protesters".