(Yicai Global) March 15 -- Beijing's two international airports have canceled over 400 flights or more than one-fifth of their total by this morning after the worst dust storm in a decade hit the country's capital city.

Beijing Capital International Airport suspended almost 250 incoming and outbound flights and Beijing Daxing International Airport stopped more than 180 flights as of 9.30 a.m. due to the sandstorm that is coming from Mongolia. But authorities predict that visibility will improve soon.

Beijing’s PM10 index exceeded the maximum level of 500 at 8 a.m. and the PM2.5 index was nearing 300, reaching serious levels of pollution, according to the municipal ecological and environmental monitoring center's website.

The worst sandstorm in Beijing over the past 10 years is moving from northwestern to northeastern China, affecting an area of nearly 1,500 kilometers, said the North China Air Traffic Management Bureau. The maximum wind speed at the border between China and Mongolia has been close to 38 meters per second, it added.

Heavy dust storms hit Mongolia on March 13, leaving six people dead and more than 80 missing, local authorities said today. Western Mongolia also suffered power outages over the weekend, local news outlets reported.

Editor: Emmi Laine, Xiao Yi