Sajjad Hussain / Getty Images Protesters shout slogans at a demonstration against India's new citizenship law in New Delhi, Dec. 19. Indians defied bans on assembly in cities nationwide as anger swelled against a citizenship law seen as discriminatory against Muslims, following days of protests, clashes, and riots that have left six dead.

Millions of mobile phones in New Delhi, India’s capital, went dead on Thursday after the city’s police department ordered the country’s largest carriers to stop voice, text, and internet services in the wake of massive protests against a controversial new citizenship law that discriminates against Muslims. Local, state, and national authorities regularly shut down the internet in India during times of unrest — 96 times this year, according to the Software Freedom Law Center, a digital advocacy group that has tracked internet shutdowns in the country since 2012. The Indian region of Kashmir has been cut off since August after India’s government revoked its autonomous legal status, and dozens of districts in five Indian states have been plunged into digital darkness in the last few days as protests have spread. But Thursday was the first time that India’s capital, home to the country’s Parliament, saw its mobile services being revoked.

Today, Delhi is seeing its first internet shutdown. The wall has been breached, it has never happened in a metropolitan city before. Shutdowns are supposed to be last-resort tools for public emergencies, not weapons to prevent dissent. #internetshutdown #CAAProtest Twitter: @ChunduruAditya / Via Twitter: @ChunduruAditya

A copy of the police department order, reviewed by BuzzFeed News and sent to all major carriers in Delhi, commanded them to halt “voice, SMS & internet” services “in view of the prevailing law and order situation.” It also provided a list of neighborhoods to which the carriers were ordered to stop service.

The shutdown came amid nationwide protests against an act that India’s Hindu nationalist government passed last week, which makes getting Indian citizenship easier for immigrants who practice all major South Asian religions except Islam. In addition to mobile phones, Indian authorities tried to clamp down on the protests by banning large gatherings, detaining thousands of people, including prominent liberal intellectuals, and periodically closing off dozens of train stations in New Delhi.

Airtel and Vodafone, two of India’s largest carriers, tweeted that they were complying with the government directive after customers in Delhi started to complain on Thursday morning.

I can confirm that there was a communication shut down in #jantarmantar for Airtel. No text, no call. The moment you are outside the protest area, it all works fine. This is definitely to not let the voice of dissent reach the masses #internetshutdown Twitter: @Nehmat_K / Via Twitter: @Nehmat_K

They deleted the tweets shortly after. Jio, India’s third major carrier, sent text messages to affected users in Delhi saying that internet services had been stopped “till further notice.” Normal service had resumed for most people by Thursday evening.

Airtel and Vodafone declined to comment. A Jio spokesperson did not respond to requests for comment. A spokesperson from India’s Home Ministry, the federal department in charge of national security, did not respond to a request for comment. More than half a billion Indians use the internet, most of them from internet-enabled smartphones. Authorities have justified cutting off access in the past by saying that it helps to prevent the spread of rumors and misinformation, but shutting down the internet also makes dissenting and organizing protests harder. “It’s really concerning that the capital city of the largest democracy in the world has shut the internet down and cut off its citizens from communicating,” said Mishi Choudhary, a technology lawyer and founder of the SFLC, in a statement. “This is unprecedented and could have an irreversible and detrimental impact on India’s aspiration to become a digital leader.”