Vinay Sharma has sought clemency on the grounds that he suffers from "mental illness".

After exhausting every legal remedy, one of the four convicts sentenced to death in the Nirbhaya case has started hunger strike in Delhi's Tihar jail. This information was part of the status report to the court, presented by the Tihar jail authorities today. Three of the convicts have exhausted the legal options available to them, the jail authorities said.

Convict Mukesh Singh, meanwhile, told the court that he did not wish to be represented by court-appointed advocate Vrinda Grover.

Convict Vinay Sharma went no hunger strike after his petition against President Ram Nath Kovind's rejection of his mercy plea was turned down by the Supreme Court last week.

The death row convict had claimed that the President had not factored in his mental illness following torture in jail. The Centre had produced a medical report dated February 12, which showed that he was mentally sound.

The trial court is hearing a plea from the parents of the woman and the Delhi government, seeking fresh death warrants for the four convicts.

The woman's parents have accused the legal system of being lenient to the perpetrators of the horrific gangrape and torture that had shocked the nation.

"It seems the judge has some sort of affection for the accused," said the father of the woman. "They are supporting them (the convicts). They don't want to hand out punishment," the woman's mother had alleged, holding a protest outside the court when the hearing was postponed.

The convicts have been using every legal loophole to delay the execution. Last month, their lawyer AP Singh had bragged to the woman's mother that "the hanging will never happen".

The four convicts, along with two others -- one of them a minor -- had gang-raped the young woman and tortured her with an iron rod in a moving bus on the night of December 16, 2012.

After fighting for life for nearly two weeks, she died on December 29 at a hospital in Singapore.

One of the assailants, just short of 18 when the crime was committed, was released after spending three years in a reform home. The main accused, Ram Singh, was found hanging in jail.

The brutality of the attack had outraged the nation bringing thousands on the streets in protest, which led to key changes in the law and security system.