Beijing's smog has started to ease, and the red alert is expected to be lifted on Thursday.
Weather authorities say cold air masses have entered the city's northwestern suburb in the early morning, and will later reach the downtown. They are bringing winds to ease the smog.
This comes two days after Beijing issued its first-ever "red alert" the highest of a four-coloured warning for pollution.
Under the red alert, Beijing banned outdoor operations on construction sites, and required some industrial plants to limit or stop production.
Car use has also been limited. But experts said authorities should work on finding long-term solutions to the pollution.