A helicopter lifts "an injured person" during an emergency drill in east China's Shanghai, June 3, 2020. A comprehensive emergency drill was held in Xuhui District of Shanghai on Wednesday. (Xinhua/Fang Zhe)

Rescuers transfer "an injured person" during an emergency drill in east China's Shanghai, June 3, 2020. A comprehensive emergency drill was held in Xuhui District of Shanghai on Wednesday. (Xinhua/Fang Zhe)

Rescuers use slip rope to evacuate "trapped people" during an emergency drill in east China's Shanghai, June 3, 2020. A comprehensive emergency drill was held in Xuhui District of Shanghai on Wednesday. (Xinhua/Fang Zhe)

Rescuers demolish the collapsed wall during an emergency drill in east China's Shanghai, June 3, 2020. A comprehensive emergency drill was held in Xuhui District of Shanghai on Wednesday. (Xinhua/Fang Zhe) 

A helicopter is seen during an emergency drill in east China's Shanghai, June 3, 2020. A comprehensive emergency drill was held in Xuhui District of Shanghai on Wednesday. (Xinhua/Fang Zhe)

Rescuers march during an emergency drill in east China's Shanghai, June 3, 2020. A comprehensive emergency drill was held in Xuhui District of Shanghai on Wednesday. (Xinhua/Fang Zhe)

Rescuers contain the spread of chemicals during an emergency drill in east China's Shanghai, June 3, 2020. A comprehensive emergency drill was held in Xuhui District of Shanghai on Wednesday. (Xinhua/Fang Zhe)