The crackdown targeted the satirically named Cockroach Janta Party (CJP) and other youth groups, which accuse Prime Minister Narendra Modi’s governing Bharatiya Janata Party (BJP) of manipulating voter lists to strengthen its electoral position ahead of crucial state elections.

Police sealed off Jantar Mantar, the designated protest site in central New Delhi, suspended mobile internet services in the business district and closed dozens of metro stations and markets.

Barricades, checkpoints and anti-riot vehicles were deployed across the capital, while security personnel searched buses and vehicles for demonstrators.

The Hindu, citing police sources, reported that nearly 2,500 people were detained in New Delhi, while Reuters, citing a Ministry of Home Affairs official, put the figure at about 2,000.

Another 600 people were reportedly arrested in Mumbai, according to the ANI news agency.

At the centre of the protests is the Election Commission’s Special Intensive Revision (SIR) of voter lists, which opposition parties say disproportionately benefits the BJP.

The controversy intensified after The Indian Express reported that two election commissioners had questioned revisions overseen by Kumar that removed roughly 130 million names from voter lists.

The Election Commission and the BJP have denied allegations of wrongdoing, while Kumar has not commented.

Authorities detained CJP founder Abhijeet Dipke and associates Saurav Das and Ashutosh Ranka aboard an Air India flight arriving in New Delhi from Mumbai.

Dipke, who shared footage of police entering the aircraft on Instagram, said he was not afraid of being arrested and accused the authorities of acting dictatorially.

Other detainees included YouTuber and Modi critic Dhruv Rathee, All India Students’ Association national president Neha Bora, Communist Party of India (Marxist-Leninist) general secretary Dipankar Bhattacharya and Supreme Court lawyer Prashant Bhushan.

Television footage also showed the detention of opposition lawmakers and former chief ministers Mamata Banerjee, Arvind Kejriwal and Pinarayi Vijayan.

Despite the arrests, smaller demonstrations continued elsewhere in the capital. Shranaya, a state committee member of the left-wing Students’ Federation of India, accused the government of undermining democracy and vowed that protesters would return to the streets.

The detentions drew international criticism. The United Nations Human Rights Office urged Indian authorities to respect peaceful assembly and engage in meaningful dialogue, while Amnesty International warned against efforts to suppress critical voices. The Committee to Protect Journalists also called on police to respect journalists after several reporters were briefly detained.

India’s mission to the United Nations in Geneva rejected the criticism as misplaced, arguing that peaceful assembly is constitutionally protected but subject to reasonable restrictions in the interest of public order.

Domestically, BJP spokesman Sambit Patra dismissed the demonstrations as a failure, saying India remained calm under the government’s leadership. Congress president Mallikarjun Kharge, however, accused Modi’s government of turning the country’s democracy into a “Muzzled Democracy”.

The unrest comes ahead of a series of important state elections beginning in early 2027, raising the political stakes for Modi’s government.

Political analyst Sanjay Kapoor told Al Jazeera that the government appeared fearful of the protests, arguing that the BJP was losing credibility and facing growing opposition.