At least seven people were killed and about 20 others injured in two separate traffic accidents on Monday in northwest China's Xinjiang Uygur Autonomous Region, Xinhua quoted traffic police as saying. A fire that broke out when a car overturned killed five people on the spot here in the regional capital just before 4 a.m. The cause of the accident is under investigation. Also, at least two people died and about 20 others were injured in a chain collision on a Turpan-Urumqi highway on Monday morning. Heavy fog caused the accident, police said, adding that visibility was less than 30 meters.