Workers transfer accessories for refitting ambulances at a workshop of a medical vehicle refit company in Qingdao, east China's Shandong Province, Jan. 30, 2020. In order to ensure the sufficient supply of ambulances during the fight against the novel coronavirus epidemic, workers of the medical vehicle refit company in Qingdao have returned to work ahead of schedule. (Xinhua/Li Ziheng)

Workers transfer accessories for refitting ambulances at a workshop of a medical vehicle refit company in Qingdao, east China's Shandong Province, Jan. 30, 2020. In order to ensure the sufficient supply of ambulances during the fight against the novel coronavirus epidemic, workers of the medical vehicle refit company in Qingdao have returned to work ahead of schedule. (Xinhua/Li Ziheng)

A worker transfers accessories for refitting ambulances at a workshop of a medical vehicle refit company in Qingdao, east China's Shandong Province, Jan. 30, 2020. In order to ensure the sufficient supply of ambulances during the fight against the novel coronavirus epidemic, workers of the medical vehicle refit company in Qingdao have returned to work ahead of schedule. (Xinhua/Li Ziheng)

A worker refits ambulance at a workshop of a medical vehicle refit company in Qingdao, east China's Shandong Province, Jan. 30, 2020. In order to ensure the sufficient supply of ambulances during the fight against the novel coronavirus epidemic, workers of the medical vehicle refit company in Qingdao have returned to work ahead of schedule. (Xinhua/Li Ziheng)