Photo taken on Jan. 4, 2017 shows the specially-built dome for athletic activities at Yuxing Campus of Huaxing Primary School in Shijiazhuang, capital of north China's Hebei Province. The dome, which is pressurized, has built-in filtration systems. Heavy smog continued to shroud north China on Wednesday. (Xinhua/Wang Xiao)
BEIJING, Jan. 4 (Xinhua) -- Heavy fog and smog continued to cause havoc across north and central China Wednesday, grounding flights and bringing traffic to a standstill.
Several expressways in Beijing -- including sections linking the capital with Harbin in the northeast, Shanghai in the east, and neighboring Tianjin Municipality -- were closed from the early hours of Wednesday until 3 p.m., according to a Weibo post by Beijing Public Security Bureau.
Beijing Nanyuan Airport had canceled 46 flights as of 11:30 a.m.
In central China's Henan Province, low visibility led to traffic restrictions on 12 expressways. The province also ordered all kindergartens and primary schools to close for the day.
The neighboring province of Shandong upgraded its alert for heavy fog from orange to red Wednesday morning, and as of noon more than 155 flights from its capital Jinan had been delayed, canceled or diverted.
Many regions have experienced heavy smog since last Friday, and it looks set to persist for the remainder of the week.
Data from Beijing Municipal Environmental Monitoring Center showed that the density of PM 2.5, particulate matter associated with hazardous smog, stood at 391 micrograms per cubic meter at noon in the city proper, indicating that the air is heavily polluted.
According to Zhang Lin'na, a meteorologist with Beijing Meteorological Station, a weak cold spell has been forecast to bring rain or snow to the Beijing-Tianjin-Hebei region from Friday to Saturday, but the pollution will not be dispersed until a strong cold front sweeps in this coming Monday night.
China has a four-tier color-coded warning system for severe weather, with red being the most serious, followed by orange, yellow and blue.