Guardian: When it comes to air pollution, the long-suffering residents of Beijing tend to think they have seen it all. But this weekend, instruments measuring the levels of particulate matter in the city's famously noxious air broke all records.
The Beijing Municipal Environmental Monitoring Centre said levels of PM2.5, tiny particulate matter, had reached more than 600 micrograms per square metre in many areas, and Reuters said it may even have hit 900 its worst-ever reading.
The World Health Organisation...