Staff members of Haikou maritime bureau patrol the course on Qiongzhou Strait, south China's Hainan Province, Feb. 21, 2018. Since Feb. 18, heavy fog has disrupted ferry services on the Qiongzhou Strait in south China, stranding passengers in cars in Haikou city. As fog started to disperse on Feb. 20 morning, ferry services resumed in two ports in Haikou, but local government advised travelers against heading to the ports before 3 p.m., as avenues leading to them remained heavily congested. Hainan, known for its tropical climate and clean air, is a popular destination for Chinese tourists during the Lunar New Year holiday. (Xinhua/Zhao Yingquan)