XI'AN, Dec. 31, 2021 Delivery rider Li Peng (1st, L) checks information for a citizen at a nucleic acid sampling site in Beilin District of Xi'an, northwest China's Shaanxi Province, Dec. 30, 2021. After the outbreak of COVID-19 in Xi'an, many delivery riders volunteer to deliver daily necessities and register information for nucleic acid test. (Credit Image: © Li Yibo/Xinhua via ZUMA Press)