Sonia Gandhi said the passing othe CAB was a "dark day" in constitutional history of India.

Congress president Sonia Gandhi on Wednesday said that the passage of the Citizenship (Amendment) Bill marks a "victory of narrow minded and bigoted forces" over India's pluralism. The controversial law which promises citizenship to non-Muslim immigrants from neighbouring was cleared by the Rajya Sabha on Wednesday, two days after being passed by the Lok Sabha, and will now go to President Ram Nath Kovind for his ascent.

Calling it a "dark day" in constitutional history of India, she reiterated Congress's determination to be relentless in its struggle against what she alleged was the BJP's "dangerously divisive and polarising agenda".

Taking on the government in a statement, the Congress leader said that the bill fundamentally challenges the idea of India that the forefathers fought for and, in its place, creates a "disturbed, distorted and divided India" where religion will become a determinant of nationhood.

She said the CAB is not just an affront to the eternal principles of equality and religious non-discrimination that have been enshrined in India's constitution, but represents a rejection of an India that would be a free nation for all her people, irrespective of religion, region, caste, creed, language or ethnicity.

"Ours is a nation that has historically offered refuge and protection to the persecuted of all nations and of all faiths. We are a proud nation that has never been broken by the insecurity of a few, for we have always stood firm with the knowledge that free India can only remain free if her people are liberated, if her voices are heard, and if our institutions, our governments and our political forces dedicate themselves to securing the inalienable rights of the citizens of this country," she said.

Sonia Gandhi also took a dig at the government over passing the Bill in the 150th birth anniversary year of Mahatma Gandhi.

The Citizenship (Amendment) Bill will let the government grant citizenship to millions of illegal immigrants who entered India from Afghanistan, Bangladesh and Pakistan before 2015 - but not if they are Muslim.

The legislation was passed 125-105 by the upper house and was hailed by Prime Minister Narendra Modi as "a landmark day for India and our nation's ethos of compassion and brotherhood".