Air quality levels have plummeted across a swath of northern China as a dust storm from Mongolia and China's Inner Mongolia Autonomous Region blows through the region.

The dust storm has caused official air quality readings to peak significantly higher than the World Health Organization's (WHO) recommended limit, the BBC reports. The WHO indicates a maximum safety level of 25 micrograms of small, breathable pollution particles per cubic metre; however, by 11 a.m. local time, the city's environmental agency said that Beijing hit 500 micrograms per cubic meter.