India's parliament passed a bill on Monday that let India grant citizenship to religious minorities persecuted in neighboring Muslim countries.

It is the first time that India has used religion as a legal basis for determining nationality.

What the bill does

Non-Muslim minorities who fled from Bangladesh, Pakistan and Afghanistan will be given Indian citizenship.

It affects Hindus, Buddhists, Jains, Christians, Sikhs and Parsis.

Eligible people who arrived before 2015 will no longer be treated as illegal immigrants.

Read more: India's BJP wants citizenship bill to counter mistakes in Assam’s NRC

Why some people oppose it: Opposition groups have blasted the bill for fundamentally altering how citizenship is decided. They say it deliberately excludes Muslims, and that it does not align with the Constitution, as it discriminates on the basis of their faith.

Why it was introduced: The bill was first introduced in 2016, fulfilling a 2014 parliamentary election promise of Prime Minister Narendra Modi's right-wing ruling Bharatiya Janata Party (BJP). It was withdrawn due to opposition, but later reintroduced. The BJP says the bill is needed as religious minorities, who otherwise face deportation, have suffered oppression in the three affected Muslim-majority countries. They insist the bill does not remove any rights of Muslims.

National citizenship register: The bill comes amid a push for a national citizenship register (NCR) that aims to root out illegal immigrants from predominantly Muslim Bangladesh. A regional version of the NCR in Assam left two million people facing statelessness. This was also criticized for specifically targeting Muslim minorities.

Watch video 02:16 Share India builds detention camps Send Facebook google+ Whatsapp Tumblr linkedin stumble Digg reddit Newsvine Permalink https://p.dw.com/p/3Q6rL Millions fear loss of citizenship in India's Assam state

Upper house test: Any bills passed in the Lok Sabha, the lower house of parliament in which BJP enjoys a majority, still need to pass the Rajya Sabha upper house, where the BJP lacks a majority.