A citizen waits for the subway at Jianshe North Road station of Subway Line 6 in Chengdu, southwest China's Sichuan Province, Dec. 18, 2020. Chengdu City, capital of southwest China's Sichuan Province, opened five new metro lines on Friday, bringing the number of metro lines in the city to 13. The new lines have brought the total length of Chengdu's far-reaching metro system to 558 km. (Xinhua/Xu Bingjie)

A citizen walks past a decorative wall at Jinfu station of Subway Line 6 in Chengdu, southwest China's Sichuan Province, Dec. 18, 2020. Chengdu City, capital of southwest China's Sichuan Province, opened five new metro lines on Friday, bringing the number of metro lines in the city to 13. The new lines have brought the total length of Chengdu's far-reaching metro system to 558 km. (Xinhua/Xu Bingjie)

A citizen takes photo at Sanguantang station of Subway Line 6 in Chengdu, southwest China's Sichuan Province, Dec. 18, 2020. Chengdu City, capital of southwest China's Sichuan Province, opened five new metro lines on Friday, bringing the number of metro lines in the city to 13. The new lines have brought the total length of Chengdu's far-reaching metro system to 558 km. (Xinhua/Xu Bingjie)

A citizen walks past a decorative wall at Southwest Jiaotong University station of Subway Line 6 in Chengdu, southwest China's Sichuan Province, Dec. 18, 2020. Chengdu City, capital of southwest China's Sichuan Province, opened five new metro lines on Friday, bringing the number of metro lines in the city to 13. The new lines have brought the total length of Chengdu's far-reaching metro system to 558 km. (Xinhua/Xu Bingjie)