空气污染困扰着中国首都

Heavy smog has returned to Beijing. The fourth bout of thick haze to hit the city this month, along with its surrounding areas.

Weather officials say an incoming cold front could clear the air pollution on Sunday, in three days time. After a summer that saw many clear blue skies, the Autumn smog has brought the pollution issue right back to the top of the public agenda.

The Beijing municipal government says several new anti-smog measures have been implemented this year, under the capital's clear air action plan, including the closure of 375 polluting factories and power stations.

On Tuesday, the municipal government issued a list of polluting production processes and outdated production equipment - things it says will be phased out. Over 600 firms have been shut down since the clear-air plan was announced in 2013. A total of 1,200 are set to be closed by the end of 2016.