(CNN) —
Deadly protests erupted in at least 15 cities in India Thursday, despite strict bans on public gatherings in several areas, as public anger over a controversial new citizenship law considered by many to be discriminatory against Muslims continues to build.
At least three people died in the violence, as thousands took to streets across the country. Two people died from injuries sustained during a protest in the city of Mangalore, in the southern state of Karnataka, a senior doctor at the Highland Hospital told CNN. One more person died from firearm injuries during a protest in Lucknow, the capital of northern Uttar Pradesh state, according to a senior doctor at the King George Medical University in the city.
In Uttar Pradesh, protesters and police violently clashed in Lucknow, with buildings and vehicles set alight. And in Sambhal city buses were torched by protesters.
In the capital New Delhi attempts by authorities to prevent demonstrations proved ineffective, as large crowds brought parts of the downtown area to a standstill.
Several metro stations were closed, with Delhi Metro Rail Corporation citing “sudden safety and security reasons.” Heavy traffic also prompted airlines Air India and Indigo to offer a full refund for all outbound domestic and international flights from the capital.
Large crowds also gathered in major cities including Mumbai, Kolkata, Hyderabad, Malegaon, and Chennai. By midday, police had detained 70 people in the southern city of Bengaluru after protesters refused to disperse from two locations.
Fueling the protests is nation-wide anger over the Citizenship Amendment Act (CAA), which was signed into law last week. The law promises to fast-track Indian citizenship for religious minorities from three neighboring countries who arrived before 2015 – but not if they are Muslim.
Critics say the law is unconstitutional as it bases citizenship on a person’s religion and would further marginalize India’s 200-million strong Muslim community.
Photos: Protesters rally against India's citizenship bill
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An Indian Muslim participates in a protest against a new citizenship law that opponents say threatens India's secular identity, in Mumbai, India, on Friday, January 24.
Photos: Protesters rally against India's citizenship bill
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A Muslim youth waves the Indian flag during a protest held by the Muslim community in Bangalore on January 24.
Photos: Protesters rally against India's citizenship bill
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A heart made of paper boats with slogans on them rests near a protest in the Shaheen Bagh neighborhood in New Delhi on Wednesday, January 16.
Photos: Protesters rally against India's citizenship bill
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Protesters light candles near posters of Mahatma Gandhi and politician and social reformer Bhimrao Ramji Ambedkar during a demonstration against India's new citizenship law at Mansoor Ali Park in Allahabad on Tuesday, January 14.
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Police personnel try to protect a man attending a protest against graffiti on the shutters and walls of Church Street condemning Indian Prime Minister Narendra Modi and India's new citizenship law in Bangalore on Tuesday, January 14.
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Activists of All Assam Students' Union and other indigenous organizations participate in a torch procession against the Citizenship Amendment Act in Guwahati, India, on Saturday, January 11.
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Protestors shout slogans outside the Delhi Police Headquarters following clashes between student groups at Jawaharlal Nehru University in New Delhi on Sunday, January 5. The violence injured around 34 people, according to police.
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Placards lie next to Indian Muslims offering prayers during a protest on Saturday, January 4.
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Policewomen detain a student protesting outside Uttar Pradesh Bhawan in New Delhi on Friday, December 27.
Photos: Protesters rally against India's citizenship bill
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Demonstrators gather at the Quddus Saheb Eidgah grounds to take part in a rally against India's new citizenship law in Bangalore on Monday, December 23.
Photos: Protesters rally against India's citizenship bill
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Demonstrators sit next to bonfires during dusk as they block a road during a protest in New Delhi on Sunday, December 22.
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Protesters gather by the Jama Masjid mosque in New Delhi to demonstrate against India's new citizenship law on Friday, December 20.
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Policemen with batons charge a protester in Ahmedabad on Thursday, December 19.
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Indians gather during a protest rally in Mumbai on December 19.
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An officer flees a police station damaged by protesters during a demonstration in Lucknow on December 19.
Photos: Protesters rally against India's citizenship bill
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Chief minister of West Bengal state and leader of the Trinamool Congress Mamata Banerjee, along with party supporters, walks in a mass rally across Howrah bridge in Kolkata on December 18.
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Students from Jamia Millia Islamia, a university in New Delhi, shout slogans during a protest on Tuesday, December 17.
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People standing on roofs in New Delhi watch police gathered next to a demonstration on December 17.
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Students and activists protest outside the Allahabad University campus in Allahabad, India, on Monday, December 16.
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People participate in a mass rally in Kolkata, India, on December 16.
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Demonstrators hold signs at the University of Mumbai.
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A bus is seen on fire following a demonstration in New Delhi on Sunday, December 15.
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A child prays during a condolence event in Guwahati, India, for demonstrators killed in anti-CAB protests.
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Demonstrators shout slogans during a protest in Guwahati on Friday, December 13.
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Relatives of Sam Stafford, 18, who was killed during clashes with police the previous day, react in Guwahati on December 13.
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Indian Muslims demonstrate against the bill in New Delhi on December 13.
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Police fire tear gas during a protest in Guwahati on Thursday, December 12.
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Indian soldiers patrol near a burnt vehicle during a curfew in Guwahati on December 12.
Photos: Protesters rally against India's citizenship bill
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An Indian police officer aims his gun before firing toward protesters who threw stones in Guwahati on December 12.
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Indian youth congress members hold torches as they demonstrate in New Delhi on Wednesday, December 11.
Photos: Protesters rally against India's citizenship bill
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Security personnel use batons to disperse students protesting against CAB in Guwahati on December 11.
Photos: Protesters rally against India's citizenship bill
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Protesters on motorbikes hold placards during a protest against the bill in Guwahati on Tuesday, December 10.
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Demonstrators shout slogans during a shutdown called by the North East Students' Organization in Agartala, India, on December 10. It was hours after lawmakers approved the government's new citizenship bill.
The Indian government had sought to quell any unrest over the law’s passing. Last week, authorities shut down the internet in four northeastern states after violent protests broke out. And on Thursday, a colonial-era law that prevents gatherings of four or more people – known as Section 144 – was imposed in three areas.
New Delhi police imposed Section 144 around the Red Fort ahead of Thursday’s protest, after police denied permission for the march. The law was also imposed in Bengaluru, and across the entire state of Uttar Pradesh – India’s largest and most populous.
Organizers of nationwide action called for people to gather regardless of the prohibitory restrictions. “Section 144 being imposed by the police is an attempt to thwart our march. This will not deter us. We will gather there for our march,” Yogendra Yadav, founder of Swaraj Abhiyaan, a group that organized the march told CNN ahead of Thursday’s march in Delhi.