China on Sunday started building a high-speed railway to link the two major southwestern cities of Chongqing and Kunming.

The construction began on a section of the 699-km-long, high-speed railway in Chongqing, which has a designed speed of 350 kph.

The railway line, with 20 stations, is expected to be completed in six years. It will slash the travel time between Chongqing and Kunming, the capital city of Yunnan province, from five hours to two hours.

The railway is designed to strengthen exchanges between central Yunan and the Chengdu-Chongqing city cluster and boost coordinated regional development.

It will also help the western regions better connect with the country's high-speed railway network and serve the Belt and Road Initiative and Yangtze River economic belt development.