Thirty people were killed in northwest China's Shaanxi province when a bus overturned and fell into a ravine on Friday afternoon, authorities confirmed.The accident happened at 3.27 p.m. when a bus carrying more than 40 passengers plunged 30 metres into a ravine in Chunhua county of Xianyang city, said an official with the county's publicity office, according to Xinhua news agency.At least 25 people died on the spot while five others, who were severely injured, succumbed while undergoing treatment.The bus belonged to the Xiangban trading company in Xi'an, Shaanxi's capital.