Police said a 29-year-old woman was travelling to her village in northern Punjab on Friday night and was the only passenger on the bus.
The driver and conductor are said to have driven her to a building where they and five others raped her repeatedly throughout the night. The driver left the woman at her village early on Saturday.
Police arrested six suspects on Saturday and were searching for another.
The gang rape of a student on a moving bus in the capital four weeks ago outraged Indians and led to calls for tougher rape laws.
The 23-year-old student later died. That attack set off an impassioned debate about how to prevent such tragedies.
Protesters and politicians have called for tougher rape laws, major police reforms and a transformation of the way the country treats women.
In her first published comments today, the mother of the dead student said all six suspects in that case, including one believed to be a juvenile, deserve to die.
She was quoted by The Times of India newspaper as saying the youngest man participated in the most brutal aspects of the rape.
Five men have been charged with the student's rape and murder and face a possible death penalty if convicted. The sixth suspect, who says he is 17 years old, is likely to be tried in a juvenile court if medical tests confirm he is a minor. His maximum sentence would be three years in a reform facility.
"Now the only thing that will satisfy us is to see them punished. For what they did to her, they deserve to die," the mother said.
Some activists have demanded a change in the law so juveniles committing heinous crimes can face the death penalty.
The name of the victim of the December attack has not been released.