For the fourth time this year, a murky haze has descended over north China, leaving residents of Beijing choking on toxic smog. China's air hasn't been this bad since 1954, according to the state-run People's Daily newspaper.
In a remarkable record of dirty air, 24 out of January's first 29 days this year had air classified as hazardous. And the skies have still not cleared.
The Air Quality Index from the U.S. embassy, designed by the U.S. Environmental Protection Agency, shows that the concentration of fine particulate matter, known as PM 2.5, has been hovering at the top of the scale since last Friday. It's in a range described as "hazardous" and calls for protective measures to be taken.
Read more at ABC News