In this aerial photo released by China's Xinhua News Agency, construction workers build a quarantine center which, according to state media, will have over 4,000 rooms to isolate close contacts of COVID-19 cases in Shijiazhuang in northern China's Hebei Province, Wednesday, Jan. 20, 2021. China is imposing some of its toughest travel restrictions yet as coronavirus cases surge in several northern provinces ahead of the Lunar New Year. (Yang Shiyao/Xinhua via AP)