The last time they had waved the Indian flag on the streets of Calcutta was when India lifted the cricket World Cup in 2011.

On Monday, Mohammed Anasul Haque, 26, and Mohammed Azim, 23, were again waving the Tricolour on a thoroughfare in the city. This time, to protest a law that “threatens to leave lakhs of people stateless across the country”.

Cousins Anasul and Azim were near the tail of a march that chief minister Mamata Banerjee was leading against the Citizenship (Amendment) Act on Monday. Neither of the youth belongs to any political party.

The former students of Saifee Hall school said they felt an urge to join the march because they wanted “to show some support to Mamata and protest an act that is grossly unjust and unfair”.

“We are carrying the flag of India and not that of any political party because we are not associated with any party. We have joined this march because we are Indians and are aggrieved by the Citizenship (Amendment) Act,” said Anasul, who runs a footwear business. “The last time we had waved the flag was when India had won the cricket World Cup.”

Azim said: “She (Mamata) is not a Muslim but she is fighting against the injustice being meted out to Muslims. So, we felt it is our duty to stand by her.”

The group of five at the protest rally on Monday afternoon. Mohammed Anasul Haque holds the Tricolour with Mohammed Azim on his left. Picture by Bishwarup Dutta

Many of the participants in the march, which was joined by thousands from all walks of life, were not associated with any political party.

The marchers carried posters and banners against the National Register of Citizens and the Citizenship (Amendment) Act and raised slogans against them.

Azim, who has studied civil engineering at the Heritage Institute of Technology, said the act was denying “some people their basic human rights”.

Three others from Anasul and Azim’s family — all students, one still in school — also joined the march.

“Discrimination based on religion” is what concerns them. Anasul said it was “grossly unfair that the act is singling out people of only one religion”.

“Just think how discriminatory it is! It says people of so many religions facing persecution would be allowed in India but doesn’t name Muslims,” he said.

All five said this was the first time they were walking in a rally called by a political leader.

“We are not associated with any political party and we are not against any political party. But the Citizenship Amendment Act is against the Constitution, which is the basic law of our country. In a way this is an attack on the country” he said.

The act allows granting citizenship to persecuted non-Muslim refugees from Bangladesh, Pakistan and Afghanistan, who arrived in India before December 2014.

The youths wanted to remind Prime Minister Narendra Modi and Union home minister Amit Shah that there was no sound logic behind the Citizenship (Amendment) Act.

“We are not saying that it is right to attack minorities in any country. What is great about India is that the Constitution calls India a secular country, whereas those (Pakistan, Afghanistan and Bangladesh) are Islamic states,” said Azim.

The cousins posed another question. “When the Prime Minister cannot show his school certificate or Rafale documents, how can he expect uneducated, poor people to keep their pre-1971 documents?” asked Azim.