A staff member tests the purification system of a negative pressure ambulance at a special-purpose vehicle company in Xi'an, northwest China's Shaanxi Province, Feb. 10, 2020. Relevant enterprises in Xi'an have responed to government's call to resume production and make negative pressure ambulances to meet the needs of hospitals in the prevention and control of the novel coronavirus pneumonia epidemic. (Xinhua/Shao Rui)
