A subway constructor wearing a mask works at the subway line 7 construction site in Nanjing, capital of east China's Jiangsu Province, Aug. 16, 2018. (Photos: Xinhua)

Despite the scorching heat wave, city-builders in Nanjing stuck to their posts outdoors to ensure the progress of construction projects.

A subway constructor works at the subway line 7 construction site in Nanjing, capital of east China's Jiangsu Province, Aug. 16, 2018.

Subway constructors work at the subway line 7 construction site in Nanjing, capital of east China's Jiangsu Province, Aug. 16, 2018.