China smog: Disruption across northern city of Harbin
21 October 2013 Last updated at 21:49 BST
There has been widespread disruption across northern China as smog brought roads and flights to a standstill.
Schools were also forced to close after visibility in parts of the northern city of Harbin in Heilongjiang province was reduced below 50m (160ft).
Celia Hatton reports.