Four men sentenced to death for the gang rape and murder of a woman on a New Delhi bus in an attack that sent shock waves across the world will be hanged on Jan. 22, an Indian court ruled on Tuesday.

The four men were convicted in 2013 of the rape, torture and murder of the 23-year-old physiotherapy student in a case that triggered large protests in India.

The attack prompted India to enact tough new laws against sexual violence, including the death penalty for rape in some cases, but implementation has been poor and the attacks have shown no signs of let-up.

In 2017, India's Supreme Court had upheld death sentences against the four men. In the last two years, the top court has dismissed review pleas filed by the convicts, paving the way for the execution.

The order to hang the four convicts on Jan. 22 came after the parents of the victim asked the court to seek death warrants against the four men.

"We have fought the legal battle with a lot of patience for more than seven years. Now, I finally get justice," the mother of the victim, who cannot be named under Indian law, told reporters after the order of the court.

Despite tough laws against sexual violence, a woman is raped every 20 minutes on average in India.

Lengthy trials, often a result of fewer courts and judges, tend to delay convictions, leaving poor, disillusioned victims with little money and patience to pursue the case.

A 23-year-old rape victim, who was set on fire by a gang of men, which included her alleged rapists, died in a New Delhi hospital last month, prompting protests.