Construction workers lay tracks at the construction site of the China-Laos railway in Southwest China's Yunnan province, on April 7, 2020. [Photo by Niu Rongjian/for chinadaily.com.cn]

Construction workers lay tracks at the construction site of the China-Laos railway in Southwest China's Yunnan province, on April 7, 2020. [Photo by Niu Rongjian/for chinadaily.com.cn]

Construction workers lay tracks at the construction site of the China-Laos railway in Southwest China's Yunnan province, on April 7, 2020. [Photo by Niu Rongjian/for chinadaily.com.cn]

Construction workers lay tracks at the construction site of the China-Laos railway in Southwest China's Yunnan province, on April 7, 2020. [Photo by Niu Rongjian/for chinadaily.com.cn]

Construction workers lay tracks at the construction site of the China-Laos railway in Southwest China's Yunnan province, on April 7, 2020. [Photo by Niu Rongjian/for chinadaily.com.cn]

Construction workers lay tracks at the construction site of the China-Laos railway in Southwest China's Yunnan province, on April 7, 2020. [Photo by Niu Rongjian/for chinadaily.com.cn]