A medical worker makes protective masks at the Second Affiliated Hospital of Xi'an Jiaotong University in Xi'an, capital of northwest China's Shaanxi Province, Feb. 7, 2020. More than 30 medical workers and volunteers have been able to make some 500 protective masks per day at the hospital. The self-made masks will be further tested, and qualified ones are going to be used for the hospital's emergency medical material reserve. (Xinhua/Li Yibo)