Police said the woman was visiting friends in Pondicherry Christmas Eve when she was abducted by three men and sexually assaulted by one of them, the BBC reported Friday. She later rejoined her friends, who were confronted by another group of men that abducted and gang-raped her, police said.
Police said all the men have confessed.
The attacks appear to be unrelated.
Two police officers were suspended for initially refusing to file a report about the assault, officials said.
The woman was reported hospitalized in stable condition.
The attacks came shortly before the first anniversary of the death of a student whose gang rape on a bus set off public outrage that led to changes in the country's sexual violence laws.