Line 9 of Chongqing metro expected to be completed in 2020

A worker welds parts on a bridge build for Line 9 of the metro system of southwest China's Chongqing Municipality, Dec. 22, 2017. The Line 9 of Chongqing metro, which is about 32.3 kilometers long, is expected to be completed in 2020. (Xinhua/Wang Quanchao)