Passengers check in on a self-service check-in kiosk at terminal 3A of Chongqing Jiangbei International Airport in southwest China's Chongqing, Dec. 17, 2018. As a major air hub in western China, Chongqing Jiangbei International Airport has received over 40 million passengers from all over the world this year. To date, the airport has opened 297 international and domestic air routes. (Xinhua/Liu Chan)