A volunteer (R) checks personal information of a resident before COVID-19 nucleic acid testing in Zhangjiajie, central China's Hunan Province, Aug. 4, 2021. Central China's city of Zhangjiajie, which has reported a cluster of the country's recent COVID-19 infections, had completed two rounds of all-inclusive nucleic acid testing as of Tuesday, local authorities said. More than 809,000 people were sampled since the city launched its first round of mass testing on July 29, said the municipal headquarters on COVID-19 prevention and control during a press conference held Wednesday afternoon. (Xinhua/Chen Sihan)