Heavy air pollution has enveloped the China's capital Beijing and surrounding areas and the weatherman on Monday said there will not be a respite until Tuesday.
The concentration of hazardous fine particulate matter known as PM 2.5 in Beijing was between 100 and 200 micrograms per cubic meter, indicating moderate pollution, the city's weather bureau said.
The city issued its first yellow alert for air pollution on Sunday, triggering restrictions on work at construction sites, outdoor barbecues and burning straw. Meteorological experts expect north China to face more smog in autumn and winter, given unfavourable weather conditions this year, state-run Xinhua news agency reported.
China has a four-tier colour-coded system for severe weather, with red being the most serious, followed by orange, yellow and blue.