Facebook-owned messaging service WhatsApp is suing India’s government over new internet rules it claims are unconstitutional and will “severely undermine the privacy” of its users, The New York Times reports. The Intermediary Guidelines and Digital Media Ethics Code, which was introduced in February and comes into effect today, contains a requirement that messaging apps identify the “first originator of information” when asked. But WhatsApp, which boasts nearly 400 million users in its largest market of India, argues that doing so would require it to trace every message sent on its service, violating users’ right to privacy.

“Civil society and technical experts around the world have consistently argued that a requirement to “trace” private messages would break end-to-end encryption and lead to real abuse,” a spokesperson for the service said in a statement. “WhatsApp is committed to protecting the privacy of people’s personal messages and we will continue to do all we can within the laws of India to do so.”

WhatsApp’s warnings about “traceability” are backed of many of the world’s biggest technology firms and digital rights groups including Mozilla, the Electronic Frontier Foundation (EFF), and the Center for Democracy and Technology. In a statement about a similar plan to mandate traceability in Brazil, the EFF said that implementing traceability “will break users’ expectations of privacy and security, and would be hard to implement to match current security and privacy standards.”

Responding to efforts by India and other countries to force it to trace messages, WhatsApp has published an FAQ on its website. It argues that this traceability requirement would force it to break the end-to-end encryption for everyone on its service, because there’s no way for it to proactively know what message a government might want to investigate ahead of time. “A government that chooses to mandate traceability is effectively mandating a new form of mass surveillance,” WhatsApp’s FAQ says.

However the Indian government argues the rules are required to track the origins of misinformation. In comments reported by Reuters, a government official argued that WhatsApp isn’t being asked to break its encryption, just to track where messages originate from.

But WhatsApp says tracing messages like this “would be ineffective and highly susceptible to abuse,” and risks punishing people for being the “originator” of content just for re-sharing information they found elsewhere. According to Reuters, WhatsApp argues that the new rules fail the tests established by a 2017 Supreme Court ruling. Namely, that privacy must be preserved except when legality, necessity, and proportionality require its infringement. WhatsApp argues that the new law lacks explicit parliamentary backing.

The lawsuit is the latest heightening of tensions between the Indian government and big tech companies. In recent months officials have ordered social media networks including Twitter, Facebook, and Instagram to remove posts critical of their handling of the pandemic. The NYT notes that social media companies have complied with many of these requests by blocking posts within the country, but keeping them visible elsewhere. While the government argues these posts could incite panic, critics say it’s using the new rules to silence detractors.

In another incident, police in India raided Twitter’s offices over a “manipulated media” label applied to a tweet from a government official.

While WhatsApp has been accused of facilitating the spread of misinformation around the world, the problem has been particularly acute in India. Since 2017, the service has been linked to a series of lynchings in the country after users on the service spread misinformation about child abductions. WhatsApp responded by placing new limits on message forwarding in an attempt to stop such accusations from going viral.