Constructors work at the construction site of Dajianshan railway tunnel of the Yuxi-Mohan Railway in Southwest China’s Yunnan province, May 25, 2019.[Photo/Xinhua]

Constructors work at the construction site of Dajianshan railway tunnel of the Yuxi-Mohan Railway in Southwest China’s Yunnan province, May 25, 2019.[Photo/Xinhua]

Constructors work at the construction site of Dajianshan railway tunnel of the Yuxi-Mohan Railway in Southwest China’s Yunnan province, May 25, 2019.[Photo/Xinhua]

Constructors work at the construction site of Dajianshan railway tunnel of the Yuxi-Mohan Railway in Southwest China’s Yunnan province, May 25, 2019.[Photo/Xinhua]