Police have arrested all three occupants of the car.
During a routine check at Sector 19 here yesterday, police had stopped the vehicle and found behaviour of the car occupants suspicious.
On checking, they found the body of the woman, identified as Poonam, resident of Mumbai, was found stuffed in a sack along with vegetables from the dicky of the car, police said.
All three occupants of the car, identified as Manohar Lal Gupta of sector 56 in Chandigarh, and a couple Rajan and Payal from sector 10 in Panchkula, have been arrested, they said.
A case under various sections including 302 (punishment for murder) of IPC have been registered against them, and they been remanded to a seven-day police custody by a local court.
Further probe is on, police said.