A disease control worker steps out of a Covid testing tent Friday in Hohhot, North China’s Inner Mongolia autonomous region. China has designated more than 1,900 Covid-19 medium and high-risk areas as the virus has spread across the country since Oct. 1. Photo: VCG

A disease control worker defumigates a village in Ji’an, East China’s Jiangxi province, on Saturday. Jiangxi reported zero local infections on Monday, but six areas remain at official risk of Covid-19 transmission. Photo: VCG

A disease control worker occupies a telephone booth in Shanghai on Sunday. The city detected 27 local cases and named 6 Covid-19 risk areas the following day. Photo: VCG

Medical workers perform a nucleic acid test on a locked-down resident in Dehong, Southwest China’s Yunnan province, on Saturday. Photo: VCG

Disease control personnel conduct a nucleic acid test on a locked-down resident through a barricade in Urumqi, Northwest China’s Xinjiang Uygur autonomous region, on Saturday. Photo: VCG

A resident displays the sticker he received after having a nucleic acid test in Xi’an, Northwest China’s Shaanxi province, on Tuesday. The city suspended offline classes on Tuesday, the day after reporting 26 new local cases. Photo: VCG

People take nucleic acid tests in Southwest China’s Chongqing on Saturday. The city reported 50 local cases on Monday. Photo: VCG

Residents of Yanhu district in Yuncheng, North China’s Shanxi province, queue for supplies outside a supermarket on Friday as the district would lock down at 3 p.m. Photo: VCG