Heavy smog that has shrouded Beijing for days is unlikely to disperse soon, environment authorities in the Chinese capital predicted on Monday.

Air pollution monitors in Beijing showed that the density of PM2.5 in some areas hit 400 micrograms per cubic meter early on Monday, well above national and international standards.

After choking in smog during the winter, Beijing enjoyed better air in March and April as strong spring winds blew away pollutants.

However, rising temperatures have stabilized the city's atmospheric structure, making winds unlikely in the next few days, according to the Beijing Municipal Environmental Monitoring Center.

The center advised residents to spend less time outdoors and avoid hard physical labor.

The smog will reduce visibility in the city to less than 3,000 meters on Monday, predicted the Beijing Meteorological Bureau.