Beijing: China on Saturday issued a hazardous air alert after a heavy blanket of smog engulfed the capital city, urging the residents here to stay indoors.
Beijing air control authorities have issued a "blue alert", the lowest of a four-level warning system this morning.
They blamed regional pollution and unfavourable weather conditions for the build-up of pollutants.
Beijing's air quality index (AQI) hit 276 at 12 pm, according to the Beijing Environmental Protection Monitoring Centre.
The office has ordered local pollution emitters to take further measures to cut emissions and advised residents to stay indoors and to wear masks when they venture out.
People suffering from respiratory and cardio-cerebrovascular diseases have been urged to reduce outdoor activities, state-run Xinhua News Agency reported.
The air is expected to gradually clear up over the next few days. Temperatures are likely to be as low as minus 7 degrees Celsius tomorrow in lowland and plain areas, according to the municipal meteorological station.