China's aviation authority has approved the construction of a major international airport in Kunming, capital of the southwestern Yunnan Province.

The construction would start later this month and was expected to be completed in three years, said a provincial government source.

The airport would be able to handle more than 20 million passengers and 600,000 tons of freight annually upon completion. Its capacity would be expanded to 60 million passengers and 1.2 million tons of freight.

It would cover 21 square kilometers in Dabanqiao town, 20 kilometers from downtown Kunming.

Investment in construction would total 23 billion yuan (294 million U.S. dollars), said Liu Zhijun, deputy director of the Airport Economic Zone in Kunming.

The airport would connect China with southeast and south Asian countries and regions, and become the fourth aviation hub after Beijing, Guangzhou and Shanghai.

It would also boost the economy and competitiveness of Yunnan, China's portal to southeast and south Asia, said Liu.