Tibet's fourth civil airport started operation today. The Gunsa airport in southwest China's Tibet Autonomous Region sits more than 4,200 meters above sea level and has a 4,500-meter runway. <br/><br/>An Airbus 319 landed at the airport in Ngari Prefecture this morning marking the airport's formal opening. Its annual throughput capacity is expected to reach 120,000 passengers by 2020. <br/><br/>Construction of the airport began in May 2007 and cost an estimated 241 million U.S. dollars. Before the airport opened, Ngari was linked to Lhasa only by road and it took three days to cover the 1,600- kilometre route.