Staff members spray disinfectant at a testing site in Chengxi District of Xining, northwest China's Qinghai Province, Nov. 8, 2021. Xining started its second round of mass nucleic acid testing at 9 a.m. on Monday. As of Nov. 7, Xining finished the first round of testing, and all swab samples from 1,448,000 citizens came back negative. (Xinhua/Zhang Long)
A medical worker takes a swab sample from a citizen for nucleic acid test at a testing site in Chengxi District of Xining, northwest China's Qinghai Province, Nov. 8, 2021. Xining started its second round of mass nucleic acid testing at 9 a.m. on Monday. As of Nov. 7, Xining finished the first round of testing, and all swab samples from 1,448,000 citizens came back negative. (Xinhua/Zhang Long)
A staff member holds QR codes for citizens to register health information at a testing site in Chengxi District of Xining, northwest China's Qinghai Province, Nov. 8, 2021. Xining started its second round of mass nucleic acid testing at 9 a.m. on Monday. As of Nov. 7, Xining finished the first round of testing, and all swab samples from 1,448,000 citizens came back negative. (Xinhua/Zhang Long)
Medical workers work at a testing site in Xining, northwest China's Qinghai Province, Nov. 8, 2021. Xining started its second round of mass nucleic acid testing at 9 a.m. on Monday. As of Nov. 7, Xining finished the first round of testing, and all swab samples from 1,448,000 citizens came back negative. (Xinhua/Wu Gang)
A staff member scans a citizen's health code to check health information at a testing site in Xining, northwest China's Qinghai Province, Nov. 8, 2021. Xining started its second round of mass nucleic acid testing at 9 a.m. on Monday. As of Nov. 7, Xining finished the first round of testing, and all swab samples from 1,448,000 citizens came back negative. (Xinhua/Wu Gang)
A medical worker takes a swab sample from a citizen for nucleic acid test at a testing site in Xining, northwest China's Qinghai Province, Nov. 8, 2021. Xining started its second round of mass nucleic acid testing at 9 a.m. on Monday. As of Nov. 7, Xining finished the first round of testing, and all swab samples from 1,448,000 citizens came back negative. (Xinhua/Wu Gang)
A staff member holds QR codes for citizens to register health information at a testing site in Chengxi District of Xining, northwest China's Qinghai Province, Nov. 8, 2021. Xining started its second round of mass nucleic acid testing at 9 a.m. on Monday. As of Nov. 7, Xining finished the first round of testing, and all swab samples from 1,448,000 citizens came back negative. (Xinhua/Zhang Long)
A medical worker takes a swab sample from a citizen for nucleic acid test at a testing site in Xining, northwest China's Qinghai Province, Nov. 8, 2021. Xining started its second round of mass nucleic acid testing at 9 a.m. on Monday. As of Nov. 7, Xining finished the first round of testing, and all swab samples from 1,448,000 citizens came back negative. (Xinhua/Wu Gang)