Agence France-Presse: Days of heavy smog shrouding swathes of northern China pushed pollution to more than 20 times safe levels on Friday, despite government promises to tackle environmental blight.
Visibility dropped dramatically as measures of small pollutant particles known as PM2.5, which can embed themselves deep in the lungs, reached more than 500 micrograms per cubic metre in parts of Hebei, a province bordering Beijing.
The World Health Organizations guideline for maximum healthy exposure is 25.
In the...