Photo taken on Jan. 17, 2018 shows a skyscraper shrouded in fog in Yangzhou, east China's Jiangsu Province. China's national observatory on Wednesday continued a yellow alert for heavy fog in some northern and eastern regions. Thick fog will sweep parts of Shandong, Henan, Anhui, Jiangsu, Hubei and Hunan provinces from Wednesday morning, according to the National Meteorological Center (NMC). (Xinhua/Meng Delong)