Schools in Beijing are closed and outdoorconstruction halted after the Chinese capitalwas issued with its first ever pollution "Red alert".
The red alert, the highest possible warninglevel, began on Tuesday morning and
will last until midday on Thursday.
Limits have been placed on car use andsome factories have been ordered to
stopoperations.
The alert comes as China, the world'slargest polluter, takes part in talks oncarbon
emissions in Paris.
China's CCTV news channel reported at
the weekend that some parts of Beijing
hadvisibility of only 200m. The order will
last from07:00 local time on Tuesday until 12:00 onThursday, when a cold front is
expected toarrive and clear the smog.
As well as limits on construction and
schools,cars with odd and even number plates will bebanned from driving on alternate days.