Beijing, Mar 15: Beijing and most of China’s northern territory witnessed the worst sandstorm of the decade, leaving hundreds of flights cancelled on Monday. Such sandstorms (comparatively low intensity ones) occur regularly in springtime as sand from western deserts blow eastwards and affect areas as far as Japan. The entire city got covered in brown dust and reduced visibility to less than 1000m. The sandstorm sent the AQI (Air Quality Index) in Beijing to 999 which is considered severely polluted. An AQI of 60 is considered safe.
