Photo shows the back of a security guard standing in front of a department store in Beijing, Jan. 29. (Photo/Wu Qiang)

A policeman carries out a spot check on a pedestrian on Wangfujing Street, Jan. 29. (Photo/Wu Qiang)

A staff member carries out his duties on a bus, Jan. 29.(Photo/Wu Qiang)

An official from the industrial and commercial administration inspects the price of commodities, Jan. 30. (Photo/Wu Qiang)

A volunteer from Weijia Community delivers food to people in quarantine, Jan. 30. (Photo/Wu Qiang)

Workers from Longfu Temple Community hurry to their posts on the morning of Jan. 31. (Photo/Wu Qiang)

Photo shows a worker performing his duties at a new post, Feb. 22. (Photo/Wu Qiang)

Photo shows a food delivery man on Yandaixiejie Street, Feb. 1. (Photo/Wu Qiang)

Police officers stand sentry in front of Bell Tower, Feb. 5. (Photo/Wu Qiang)

Photo shows a delivery man smiling, Feb. 5. (Photo/Wu Qiang)

Citizens work together to shovel ice, Feb. 6. (Photo/Wu Qiang)

A sanitation worker sweeps the roads after heavy snow, Feb. 6. (Photo/Wu Qiang)

A food delivery man at work, Feb. 6. (Photo/Wu Qiang)

Photo shows a security guard carrying out his duties in Chaoyang district, Feb. 11. (Photo/Wu Qiang)

A store selling steamed buns comes up with a new way of preventing cross-infection during the epidemic, Feb. 13. (Photo/Wu Qiang)

An ambulance comes to rescue a senior citizen suffering from heart disease in Dongcheng district, Feb. 13. (Photo/Wu Qiang)

Photo shows a sanitation worker working in heavy snow, Feb. 14. (Photo/Wu Qiang)

Photo shows a volunteer who is also a member of the Communist Party of China working in the snow, Feb. 14. (Photo/Wu Qiang)

Photo shows a community worker working in the snow, Feb. 14. (Photo/Wu Qiang)

Photo shows a staff member taking the body temperature of a pedestrian, Feb. 16. (Photo/Wu Qiang)

Photo shows strict epidemic prevention and control measures taken at a food market, March 2. (Photo/Wu Qiang)

Photo shows a designated worker clearing the garbage of citizens in self-quarantine at home, Feb. 14. (Photo/Wu Qiang)

A community worker remains ever vigilant, even at lunch, March 4. (Photo/Wu Qiang)

Photo shows a sanitation worker sprinkling water on streets, March 4. (Photo/Wu Qiang)

A sanitation worker wears a filter-type mask, March 7. (Photo/Wu Qiang)

Online shopping becomes a favourite option for many people, March 12.(Photo/Wu Qiang)

A worker carries out disinfection on a regular basis, March 7. (Photo/Wu Qiang)

Photo shows two officers patrolling in front of the Palace Museum, March 14. (Photo/Wu Qiang)