Beijing hit by third sandstorm in five weeks

Dust blown in from drought-hit areas to the north sends pollution soaring to twice the hazardous level

The third major sandstorm in five weeks turned Beijing's skies sepia on Thursday, and sent air quality plummeting in the Chinese capital.

The storms, caused by winds from drought-hit Mongolia and north-western China, sent levels of the pollutant PM10, which can penetrate the lung, to 999 micrograms per cubic metre - a level almost double the hazardous" stage indicated by the Beijing air pollution real time quality index.