'India's Daughter', the documentary based on the 2012 Delhi gang-rape, holds a mirror to the society and its mindset, and should be watched by everybody, Nirbhaya's father said today, questioning the ban on its screening in India.

"Everyone should watch the film. If a man can speak like that in jail, imagine what he would say if he was walking free," said the father of the young woman who was brutally gang-raped, tortured and killed by six men, including a 17-year-old, on a moving bus.

The woman came to be known as "Nirbhaya" or fearless, and became a symbol for India's fight to check crimes against women.

"The documentary exposes what is happening. I don't understand why it was banned. But if the country has taken a decision, we have to support it," he told NDTV.

The documentary by British filmmaker Leslee Udwin, which includes interviews of Nirbhaya's parents, doctors, the police, lawyers and one of the rapists, was aired by the BBC on Wednesday night.

Mukesh Singh, one of the four men sentenced to death for the horrific rape and murder, has said in an interview from jail that the woman was to be blamed, displaying complete lack of remorse.

On Wednesday, the government said it would not allow the film's screening and investigate how permission was granted for the rapist's interview. But as Parliament debated it, there were strong voices against the ban.

"Talking in Parliament does not help. Why are the convicts still alive? Why have they not been hanged yet? Who are they to tell a woman what to wear or what to do? How will the campaign 'Beti Padao, Beti Bachao' (educate, save our daughters) work if our daughters are not alive?" Nirbhaya's father said.

He felt that a ban would only make people more curious.

Nirbhaya's mother said, "It is not about the ban. Why are these convicts still alive? It seems we will die fighting for justice but they will outlive us."