Beijing air control authorities issued a hazardous air alert and urged residents to stay indoors as a heavy blanket of smog covered the city on Saturday.
The city's office for severe air pollution emergency response issued a "blue alert", the lowest of a four-level warning system, on Saturday morning, blaming regional pollution and unfavorable weather conditions for the build-up of pollutants.
Beijing's air quality index (AQI) hit 276 at 12 p.m., according to the Beijing Environmental Protection Monitoring Center.
The office has ordered local pollution emitters to take further measures to cut emissions and advised residents to stay indoors and to wear masks if venturing out. Children, the elderly and those who suffer respiratory and cardio-cerebrovascular diseases have been urged to reduce outdoor activity.
The air is forecast to gradually clear up the over the next few day as strong gales from the north are expected to arrive on Sunday and will last until next Thursday.
Temperatures are likely to be as low as minus 7 degrees Celsius on Sunday in lowland and plain areas, according to the municipal meteorological station.
An AQI of over 300 is defined as "serious pollution" and an AQI between 201 and 300 is considered "heavy", according to China's standards.