The woman had gone public with her rape ordeal and had identified herself on television after the 2012 Delhi gangrape case.
"She passed away in the morning. She was suffering from health problems and got admitted to a city hospital for the last few days," Joint Commissioner of Police (Crime) Pallab Kanti Ghosh told PTI.
According to the police, she was suffering from encephalitis and was admitted to School of Tropical Medicine. She died of multi-organ failure at 3 AM.
The woman, who was in her mid-30s during the incident, was raped in a moving car in Park Street area on February 6, 2012, by five young men who picked her up from outside a pub.
Also Read
While three of the accused are behind bars, two others, including the prime accused, are still at large.
The incident had triggered nationwide outrage as the administration initially termed it as a fabricated case to malign the authorities.
Chief minister Mamata Banerjee had courted controversy at that time by saying the incident was "fabricated".