Medical workers collect throat swabs from local residents at a nucleic acid testing site at a community in Balizhuang Street of Haidian District, Beijing, capital of China, June 23, 2020. Communities in Beijing have taken strict measures, including sterilizing key areas and conducting nucleic acid tests on local residents, to prevent and control the spread of the COVID-19 pandemic. (Xinhua/Ren Chao)

Medical workers verify information of local residents at a nucleic acid testing site at a community in Balizhuang Street of Haidian District, Beijing, capital of China, June 23, 2020. Communities in Beijing have taken strict measures, including sterilizing key areas and conducting nucleic acid tests on local residents, to prevent and control the spread of the COVID-19 pandemic. (Xinhua/Ren Chao)

A community worker delivers a package for home-isolated residents at a community in Balizhuang Street of Haidian District, Beijing, capital of China, June 23, 2020. Communities in Beijing have taken strict measures, including sterilizing key areas and conducting nucleic acid tests on local residents, to prevent and control the spread of the COVID-19 pandemic. (Xinhua/Ren Chao)

A community worker disinfects packages at a community in Balizhuang Street of Haidian District, Beijing, capital of China, June 23, 2020. Communities in Beijing have taken strict measures, including sterilizing key areas and conducting nucleic acid tests on local residents, to prevent and control the spread of the COVID-19 pandemic. (Xinhua/Ren Chao)

A worker disinfects fitness equipment at a community in Balizhuang Street of Haidian District, Beijing, capital of China, June 23, 2020. Communities in Beijing have taken strict measures, including sterilizing key areas and conducting nucleic acid tests on local residents, to prevent and control the spread of the COVID-19 pandemic. (Xinhua/Ren Chao)

A worker disinfects garbage cans at a community in Balizhuang Street of Haidian District, Beijing, capital of China, June 23, 2020. Communities in Beijing have taken strict measures, including sterilizing key areas and conducting nucleic acid tests on local residents, to prevent and control the spread of the COVID-19 pandemic. (Xinhua/Ren Chao)

A worker sprays disinfectant over plants at a community in Balizhuang Street of Haidian District, Beijing, capital of China, June 23, 2020. Communities in Beijing have taken strict measures, including sterilizing key areas and conducting nucleic acid tests on local residents, to prevent and control the spread of the COVID-19 pandemic. (Xinhua/Ren Chao)

Medical workers verify information of local residents at a nucleic acid testing site at a community in Balizhuang Street of Haidian District, Beijing, capital of China, June 23, 2020. Communities in Beijing have taken strict measures, including sterilizing key areas and conducting nucleic acid tests on local residents, to prevent and control the spread of the COVID-19 pandemic. (Xinhua/Ren Chao)

A medical worker collects a throat swab from a local resident at a nucleic acid testing site at a community in Balizhuang Street of Haidian District, Beijing, capital of China, June 23, 2020. Communities in Beijing have taken strict measures, including sterilizing key areas and conducting nucleic acid tests on local residents, to prevent and control the spread of the COVID-19 pandemic. (Xinhua/Ren Chao)

A worker disinfects a residential building at a community in Balizhuang Street of Haidian District, Beijing, capital of China, June 23, 2020. Communities in Beijing have taken strict measures, including sterilizing key areas and conducting nucleic acid tests on local residents, to prevent and control the spread of the COVID-19 pandemic. (Xinhua/Ren Chao)

A worker disinfects fitness equipment at a community in Balizhuang Street of Haidian District, Beijing, capital of China, June 23, 2020. Communities in Beijing have taken strict measures, including sterilizing key areas and conducting nucleic acid tests on local residents, to prevent and control the spread of the COVID-19 pandemic. (Xinhua/Ren Chao)

A community worker delivers a package for home-isolated residents at a community in Balizhuang Street of Haidian District, Beijing, capital of China, June 23, 2020. Communities in Beijing have taken strict measures, including sterilizing key areas and conducting nucleic acid tests on local residents, to prevent and control the spread of the COVID-19 pandemic. (Xinhua/Ren Chao)

A medical worker collects a throat swab from a local resident at a nucleic acid testing site at a community in Balizhuang Street of Haidian District, Beijing, capital of China, June 23, 2020. Communities in Beijing have taken strict measures, including sterilizing key areas and conducting nucleic acid tests on local residents, to prevent and control the spread of the COVID-19 pandemic. (Xinhua/Ren Chao)