The official Xinhua News Agency says the bus carrying 21 people was traveling on a mountain road in Sichuan province's Aba prefecture when it overturned and fell into the ravine at around noon Tuesday. Six people injured in the accident were taken to a hospital.
Aba has a large Tibetan population, but Xinhua didn't give the ethnicity of the victims.
Road safety is a serious problem in China, with many accidents caused by poorly maintained roads and bad driving habits.
