People wearing face masks queue up to purchase masks at a pharmacy in Tai Po district in Hong Kong as a preventive measure to protect themselves against the novel coronavirus on Jan 28, 2020. (EDMOND TANG / CHINA DAILY)

A queue of people waiting to buy face masks is seen in Tai Po, Hong Kong, on Jan 28, 2020. (EDMOND TANG / CHINA DAILY)

People wearing face masks queue up to buy masks at a shopping mall in Tai Po, Hong Kong, on Jan 28, 2020. (EDMOND TANG / CHINA DAILY)

A group of people wearing face masks queue up to buy face masks outside a shop in a shopping mall at Tai Po, Hong Kong, on Jan 28, 2020. (EDMOND TANG / CHINA DAILY)

Residents wait to buy face masks as a notice informing customers that masks are sold out is seen outside the shop in a shopping mall in Tai Po, Hong Kong, on Jan 28, 2020. (EDMOND TANG / CHINA DAILY)