BEIJING - A widespread fog effecting the North China region including Beijing and Tianjin has grounded hundreds of flights Saturday morning.

Passengers wait at the Beijing Capital International Airport on March 17, 2012. [Photo/Xinhua]

The Beijing Capital International Airport said by 9 am, 199 flights were canceled, as the visibility at the airport was less than 200 meters.

Meanwhile, airports in Tianjin, Shijiazhuang, Zhengzhou in North China were all enveloped in dense fog Saturday morning, with the visibility in Tianjin's airport less than 50 meters.

The fog has stagnated air pollutants. The averaged PM2.5 air quality reading in Beijing from Friday night to Saturday morning hit 144 micrograms of fine particles in per cubic meter of air.

The Municipal Meteorological Station said a gale following a drizzle Saturday evening would help dissipate the smog, but bring down the temperature by 10 degrees Celsius.