![A man walks in a park in thick fog in Bozhou, east China\'s Anhui Province, Nov. 13, 2018. (Xinhua/Zhang Yanlin)](http://www.ecns.cn/hd/2018/11/14/b2c471a1d17c437ab4cbd06f76740242.jpg)
A man walks in a park in thick fog in Bozhou, east China's Anhui Province, Nov. 13, 2018. (Xinhua/Zhang Yanlin)
![A park is cloaked with thick fog in Bozhou, east China\'s Anhui Province, Nov. 13, 2018. (Xinhua/Zhang Yanlin)](http://www.ecns.cn/hd/2018/11/14/5ef23939ee5a40ab911b8409dadc08c3.jpg)
A park is cloaked with thick fog in Bozhou, east China's Anhui Province, Nov. 13, 2018. (Xinhua/Zhang Yanlin)
![Citizens walk in a park in thick fog in Handan, north China\'s Hebei Province, Nov. 13, 2018. (Xinhua/Cheng Xuehu)](http://www.ecns.cn/hd/2018/11/14/ef51b5234ea2419797e8b8444b8ad024.jpg)
Citizens walk in a park in thick fog in Handan, north China's Hebei Province, Nov. 13, 2018. (Xinhua/Cheng Xuehu)
![Photo taken on Nov. 13, 2018 shows vehicles and citizens moving in thick fog in Xingtai, north China\'s Hebei Province. (Xinhua/Huang Tao)](http://www.ecns.cn/hd/2018/11/14/0f5dc9ea814b45728ceb316f3bcb8115.jpg)
Photo taken on Nov. 13, 2018 shows vehicles and citizens moving in thick fog in Xingtai, north China's Hebei Province. (Xinhua/Huang Tao)
![A citizen is seen doing morning exercise in a park in thick fog in Xingtai, north China\'s Hebei Province, Nov. 13, 2018. (Xinhua/Chen Lei)](http://www.ecns.cn/hd/2018/11/14/dc31a6e0c37f48a29519567108b0fe91.jpg)
A citizen is seen doing morning exercise in a park in thick fog in Xingtai, north China's Hebei Province, Nov. 13, 2018. (Xinhua/Chen Lei)
![Citizens walk in a park in thick fog in Handan, north China\'s Hebei Province, Nov. 13, 2018. (Xinhua/Cheng Xuehu)](http://www.ecns.cn/hd/2018/11/14/920586ce9e5f4bea89d45ad40395f9ec.jpg)
Citizens walk in a park in thick fog in Handan, north China's Hebei Province, Nov. 13, 2018. (Xinhua/Cheng Xuehu)