Beijing was shrouded in sand on Tuesday with a yellow sky for the second time this spring.

Windows in office buildings and households had to be closed. Normally, they would be opened at the early morning to introduce fresh air.

"At 8 AM today, Beijing monitored floating dust in the air," Duan Li, Beijing Meteorological Observatory's chief forecaster, told Xinhua.

On Monday, a strong sandstorm emerged in central Mongolia that borders north China. Strong cold air, which was blowing from the far northwest and rolled up sand and dust along its way, had caused the weather, said Duan. Inner Mongolia and northwestern Hebei, had also witnessed the sandy weather prior to its arrival in Beijing.

The sand would begin to dissipate on Tuesday afternoon and the weather in the city was expected to clear by Thursday, Duan said.

The first dusty weather hit Beijing on March 1.

The meteorological observatory estimated the capital would have about 10 sandy days in spring, near the annual average.

(Xinhua News Agency March 18, 2008)