Photo shows medical N95 masks on a production line of a mask production company in southwest China's Chongqing, Feb. 17, 2020. Medical N95 masks will be supplied to the novel coronavirus epidemic prevention frontline for medical workers. (Photos: Xinhua)

Workers perform disinfection at the workshop for medical N95 masks at a mask production company in southwest China's Chongqing, Feb. 17, 2020. Medical N95 masks will be supplied to the novel coronavirus epidemic prevention frontline for medical workers.

Workers produce medical N95 masks at a mask production company in southwest China's Chongqing, Feb. 17, 2020. Medical N95 masks will be supplied to the novel coronavirus epidemic prevention frontline for medical workers.

A worker produces medical N95 masks at a mask production company in southwest China's Chongqing, Feb. 17, 2020. Medical N95 masks will be supplied to the novel coronavirus epidemic prevention frontline for medical workers.

Workers produce medical N95 masks at a mask production company in southwest China's Chongqing, Feb. 17, 2020. Medical N95 masks will be supplied to the novel coronavirus epidemic prevention frontline for medical workers.

A worker produces medical N95 masks at a mask production company in southwest China's Chongqing, Feb. 17, 2020. Medical N95 masks will be supplied to the novel coronavirus epidemic prevention frontline for medical workers.