Technicians debug firefighting robots just off the production line at a firefighting robot factory in Tangshan, North China’s Hebei province, March 26, 2019. [Photo/Xinhua]

A worker is seen on a production line at a lithium battery manufacturing plant for automotive use in Tangshan, North China’s Hebei province, April 11, 2019.[Photo/Xinhua]

A worker is seen on the production line of an automobile transmission manufacturer in Fengrun district in Tangshan, North China’s Hebei province, April 12, 2019. [Photo/Xinhua]

A worker is seen on a production line at a lithium battery manufacturing plant for automotive use in Tangshan, North China’s Hebei province, April 11, 2019. [Photo/Xinhua]

A worker is seen at a lithium battery manufacturing plant for automotive use in Tangshan, North China’s Hebei province, April 11, 2019. [Photo/Xinhua]