Beijing (TIP) : The skies above Beijing turned yellow and air pollution soared to severe levels as a giant cloud of sand and dust particles rolled into the city, propelled by strong winds from the north of China. Beijing’s air quality index rose to 324 as of 4 p.m. local time (0800 GMT) on Thursday, mainly due to larger particles of sand and dust, municipal authorities said. It worsened in the evening, exceeding 1,300 in some parts of the city, according to the Swiss IQAir app. The particles originated from Mongolia and the Chinese region of Inner Mongolia, and high winds are expected to carry the pollutants to central and eastern China by Friday, the China Meteorological Administration said. Reuters