Tianjin authorities issued a yellow alert for heavy fog on Sunday morning, just two days after issuing a red alert for air pollution. Many parts of the municipality suffered from a visibility of less than 500 meters, disrupting flights and causing highways to be closed. Twenty-seven flights were delayed and eight canceled over the course of the morning, but as the weather conditions improved, all flights have resumed to normal. Most highways in the city remain closed. China's meteorological alerts are categorized as blue, yellow, orange and red as the severity increases. http://www.cctvplus.com/news/20161218... Subscribe us on Youtube: / cctvplus CCTV+ official website: http://www.cctvplus.com/ LinkedIn: / cctv-news-content Facebook: / newscontent.cctvplus Twitter: / cctv_plus