Following are the 10 developments in this story:
Of the six men arrested in the case, one was a juvenile. Another, Ram Singh, who was driving the bus, was found hanging in jail in March 2013. His lawyers had alleged that he had been murdered.
The other four -- Akshay, Vinay Sharma, Pawan and Mukesh -- were found guilty and sentenced to death by the Delhi High Court in September 2013.
The men have challenged the death sentence in Supreme Court, which is currently hearing their appeal.
The top court has put a freeze on the death sentence. The court said it would sit for extra time to hear their appeal.
In August, one of the convicts, Vinay Sharma, had taken a lot of painkillers and tried to hang himself with a towel in Delhi's high security Tihar Jail. He was spotted by the guards in time.
The alleged involvement of the juvenile - who was six months short of 18 years - had created a huge stir in the country, triggering a demand to give teeth to criminal laws. At the time, the maximum punishment for minors was three years at a reform centre.
Later, parliament amended the Juvenile Justice Act, under which minors aged 16 years or older can be tried as adults in cases involving heinous crimes like rape or murder. The decision whether a minor would be tried as an adult rests with the Juvenile Justice Board.
After serving the three-year term, the juvenile was released on December 2015, triggering widespread anger. But a court, while agreeing that the issue was serious, said after December 20, the juvenile cannot be kept at a special home as per law.
This year, the government has allocated Rs 200 crore to the fund set up in memory of Nirbhaya. The Nirbhaya fund, as it is known, supports government initiatives to protect women and children from sexual crimes and provide compensation for survivors.
The Nirbhaya case had drawn visceral response from the nation. Protests and candlelight marches held across all metros. The biggest of these were held in Delhi, where thousands of students braved tear gas shells and water cannons at the India Gate in bitter winter.