These pictures show what happened in Delhi on Sunday

This is how it happened from the beginning —Tensions erupted in south Delhi on Sunday as two buses were allegedly set on fire in protest against the controversial Citizenship Act. (Express photo: Gajendra Yadav)

Police alleges that the protesters torched DTC buses and damaged a fire tender that was pressed to service to douse the flames. (Express photo: Gajendra Yadav)

As the protest erupted into violence by 4:30 pm Sunday, protesters were pushed back from Sarai Jullena and New Friends Colony, and Jamia’s campus came under siege by 6:30 pm with teargas shells being thrown inside and police raiding the canteen and mosque. (Express Photo by Gajendra Yadav)

According to protesting students, when they reached Mata Mandir, police began a lathi charge against them around 4:30 pm and deployed tear gas to disperse them. (Express Photo by Gajendra Yadav)

An estimated 1,000 protesters clashed with police and at least six buses and over 50 vehicles were set ablaze in Mathura Road, New Friends Colony, Jamia Nagar and Sarai Julena on Sunday. (Express photo: Gajendra Yadav)

Delhi Police personnel surround and beat students of Jamia Millia Islamia (Express photo by Gajendra Yadav)

Students being led out of the Jamia campus with their hands raised. (Reuters)

University authorities, meanwhile, dissociated themselves from the protests and said local residents were indulging in stone-pelting and arson. (Express photo: Gajendra Yadav)

This is the second flare-up in the National Capital after 27 people were detained following clashes with police during a protest against the law last Friday outside the campus, involving Jamia students and local residents. (Express photo by Gajendra Yadav)

According to Delhi Fire Service, protesters blocked the way of one of the fire tenders and damaged it. Two firemen were also injured in the violence, they said. (Express photo: Gajendra Yadav)

Protesters claimed that the police baton charged them when they were holding a peaceful protest, news agency PTI reported. (Express photo: Gajendra Yadav)

Meanwhile, the Jamia Millia Teachers' Association has condemned the violence witnessed on Mathura road and Sarai Juleina. (Express photo: Gajendra Yadav)

Vehicles coming from Badarpur and Ashram Chowk were diverted to alternative routes due to the blockade. (Express photo: Gajendra Yadav)

Soon after the violence in South Delhi, police entered the Jamia Millia Islamia campus and blocked the university gates. (PTI photo)

Jamia students claim that "certain" local elements had "disrupted" their protest and indulged in violence. (PTI photo)

Ambulances were allowed inside the campus around 8 pm. The vehicles filled up within minutes and rushed towards nearby hospitals. (Express photo: Gajendra Yadav)

Later, students from Delhi University and JNU called for another protest at 9 pm outside the old police headquarters in ITO. (Express photo: Abhinav Saha)

Among those who turned up were CPI’s D Raja, CPI(M)’s Brinda Karat, Bhim Army chief Chandrashekhar Azad. (Express photo: Abhinav Saha)

Protests outside the old Police HQ at ITO on Sunday night. (Express photo: Abhinav Saha)

As many as 50 students, who were detained during protests at the Jamia Millia Islamia University against the contentious Citizenship (Amendment) Act in the national capital, were released in the wee hours of Monday. (Express photo by Gajendra Yadav)