CHONGQING, Jan. 9 (Xinhua) -- A total of 663 freight train trips were made between southwest China's Chongqing municipality and Europe in 2017, local authorities said.

This brings the total number of such trips between Chongqing and Europe to 1,500 since the city launched the service in 2011.

Demand for rail freight between China and Europe, an alternative to slower and riskier sea freight and much costlier air cargo, has exploded in recent years.

About 35 Chinese cities operate cargo trains to Europe.