Climate crisis

A virtual tour of Beijing's Mars-like sandstorms

The science behind sandstorm pollution, explained.

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Beijing made headlines this week, as skies turned dark orange — echoing a scene out of a post-apocalyptic movie.

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The air quality index (AQI) reached a shocking 999 rating on Monday, indicating hazardous levels of air pollution. Good AQI typically falls between 0 and 50.