The 29-year-old woman said the bus driver and one man on the bus took her to an undisclosed location where five other men joined to rape her throughout the night Friday in Gurdaspur district in Punjab.
Police said they are searching for the seventh suspect, CNN reported Sunday.
"They threatened me with a sharp edged weapon and did wrong things with me," said the alleged victim, whose name was not reported. "They kept me confined all through the night and forced me to do what they want."
The case is similar to another incident of gang rape aboard a bus Dec. 16 in New Delhi. The attackers raped a 23-year-old woman and brutally beat her and her male companion before dumping them by the side of the road. The woman later died of her injuries.
The incident sparked rallies throughout India over the treatment of women.