Beijing residents are hoping that winds forecast for today will blow away severe smog and prevent the first use of new emergency air pollution measures that will close schools and curb traffic.
The capital is being forced to consider the restrictions after the city's air quality index (AQI) shot above 300 late on Friday night and remained there yesterday. The municipal government issued its third blue alert in a week to notify the public that the air was "highly polluted".
A monitoring station at the US embassy showed the air was "hazardous", with readings of PM2.5 - particles smaller than 2.5 microns and thought to be most damaging to people's health - higher than 400 micrograms per cubic metre. That was more than 20 times the World Health Organisation's recommended daily limit of 20 micrograms.
Many people throughout northern China opted to stay indoors yesterday as visibility in some areas fell to 20-30 metres, according to China National Radio. The smog was blamed for delays and cancellations of several flights at Beijing Capital International Airport and the closure of at least 16 highways leading to and from Beijing.
Some commuters wondered whether they would be able to go to work tomorrow, or if emergency measures announced on October 16 would be activated.
Facing such speculation, municipal environmental protection authorities told The Mirror newspaper the alert would likely not be raised unless heavy pollution lasted for three days. Forecasters expected winds to blow the smog away before tomorrow.
If the plan is activated, schools will be closed, private cars limited to using roads on alternate days and 80 per cent of government-owned cars parked.
A satellite image from the China Meteorological Centre (CMA) showed at least 10 provinces, including Hebei , Henan and Liaoning , shrouded by smog. Some cities had issued red alerts, the most serious warning level.
This year has seen the highest number of smoggy days since 1961, the CMA said on Friday. The China News Service reported that there had been 2.3 times more smoggy days than average.
"The air makes me despair," wrote one Sina Weibo user. "I feel like I'm living in a smoking chimney." While some focused on their health, others were more concerned with the countermeasures. "What changes has our government made since PM2.5 became the symbol of Beijing?" asked one microblogger.
Concerns about smog on the mainland reached new heights after the capital's AQI topped 700 in January. The pollution has been blamed with deterring tourists, with visits down by half in the first three quarters of the year.