Citizens keep social distance while waiting for COVID-19 nucleic acid testing in Zhangjiajie, central China's Hunan Province, Aug. 10, 2021. Since the recent resurgence of COVID-19 in Zhangjiajie from July 29, the city has reported 53 locally-transmitted confirmed cases, and three asymptomatic carriers are currently under medical observation. (Xinhua/Chen Sihan)