On Sunday night in Delhi, students protesting the newly-passed Citizenship Amendment Act (CAA) were brutalised by the police. The police attack was focused on one university, Jamia Millia. Similar scenes of teargas, arson and bloodshed were seen at the Aligarh Muslim University in the state of Uttar Pradesh. Both are seen as “Muslim” institutions, although students of all religions may study there. As news of police using disproportionate force against students spread across India via social media, students from other universities as well as concerned citizens joined them on the streets. Since then, the protests have not stopped; several more are planned over the coming week.

What is the Citizenship Amendment Act (CAA) and why has it thrown India into turmoil? The act grants fast-tracked Indian citizenship to previously illegal immigrants who entered the country before 2015, and who are Hindu, Sikh, Buddhist, Jain and Parsi, as well as to Christians from Afghanistan, Bangladesh and Pakistan. Crucially, the act excludes Muslims.

The CAA comes hot on the heels of the disastrous National Register of Citizens (NRC) in the state of Assam, which has been used to purge the region of illegal immigrants and sent 1.9 million now stateless people to detention centres.

The move is thus perhaps unsurprising, given that the goal of Narendra Modi’s Hindu-supremacist Bharatiya Janata Party (BJP), re-elected with a massive majority in May, is that India is perceived as a safe haven for all religions – except Islam. Then again, it is somewhat ironic that for decades the northeast of India has claimed that migration from Bangladesh has diluted their tribal and ethnic identities, something that the CAA will potentially allows to continue.

The CAA attacks a central tenet of Indian Constitution. The country’s formation as a democratic republic in 1947 was grounded in secularism. Unlike Pakistan, which was formed as an expressly religious state, India was emphatically not. Narendra Modi’s government is not making any bones of its intention not to treat all Indians equally.

In a campaign speech this week in the state of Jharkhand, Modi said protesters against the CAA could be “recognized by their clothes” – a clear reference to Muslims. Home minister Amit Shah, who has referred to illegal immigrants as “termites”, mocked protesters: “Say you will allow all Muslims into India”. There is no hiding any more: the two most powerful men in India’s government have now made their Hindu-supremacist and Islamophobic agenda completely clear.

For India’s Muslims, the CAA stokes fears of becoming second-class citizens. Families have been torn apart by the NRC; soldiers who have won medals for their bravery are now in detention centres simply for being Muslim. If the NRC can do so much damage in one state, what horrors now lie in store for the rest of the country’s Muslim population?

Both the NRC and CAA have shaken India to its core. It is bad enough that the economy is in chaos; that the state of Kashmir has been under lockdown since August; that all the promised development has not arrived. Now India itself, and the Constitution which sets us apart, has been compromised – though at last, the fightback has begun. The Supreme Court may have deferred all petitions against the act to the end of January – yet public protests are sweeping the country.

Even the BJP’s political and ideological allies, people who supported the Citizenship Amendment Bill in Parliament, have found themselves forced to backtrack in the face of public outrage. India’s enormous and popular film industry has been scrutinised for not speaking out on its injustice; Hollywood star John Cusack shamed his Indian colleagues by expressing solidarity with the student protesters.

It is all too easy, however, to be lulled into a false sense of security that the movement against Constitutional destruction is gaining momentum. These are early days. Given the power the BJP draws from its large parliamentary majority, it is unlikely that the government will change course yet, if at all. Unless India’s many opposition parties come together to speak in one voice, they pose no challenge right now.