Two expressway sections near Beijing were closed after snow fell from around 7 p.m. on Thursday, and the Beijing Meteorological Station issued its lowest-level alert for heavy snow.

At Beijing Capital International Airport, where the visibility was reduced to 1,200 meters on Friday morning, the snowy weather had resulted in the cancellation of 51 flights by 8:50 a.m., with another 22 delayed, according to the airport.

As of 8 a.m. on Friday, snowfall in urban areas reached on average 4.7 mm, and snow in some areas reached 2 to 5 cm, according to data provided by the station.

Some primary schools received a circular from education authorities that they should close by noon to reduced the strain on traffic.

Snow also hit Beijing's nearby provinces and cities. In Shandong Province, 60 expressway toll gates were closed on Friday because of snow.

Elsewhere, at least three people were killed and several others injured at around 8:50 a.m. on Friday in a pile-up involving more than 10 vehicles on a snow-coated section of the expressway from the provincial capital of Jinan to Guangzhou in Pingyin County, according to provincial traffic management authorities.

Flight operations at the airport of Jinan were affected on Thursday evening but were restored on Friday.

Beijing started to use environmentally friendly snowmelt agent on some major road sections on Friday, according to the capital's municipal affairs administration commission.

The liquid agent contains no pollutants such as chloride, sulfate or nitrite, so will not affect the road surface and plants by the wayside.

Nevertheless, the commission said it will try to limit usage of the snowmelt agent and avoid it entirely in areas including Tian'anmen Square, residential areas and parks.

The snowfall ended on Friday afternoon. But at 4 p.m., the Beijing Meteorological Station released an orange warning on fog and a yellow icy-road warning.

China has a four-tier color-coded weather warning system: red, orange, yellow and blue. Red is the most serious level.