Thunder showers are expected to hit Beijing late Sunday and are likely to disperse lingering smog, according to the city's weather bureau.

Smog blanketed the city starting on Sunday morning. As of 2 p.m., 30 of the city's 35 air quality monitoring stations gave readings indicating light to medium pollution, said an official with the city's environmental monitoring center.

Levels of the major pollutant PM2.5, or airborne particles measuring 2.5 microns or less in diameter, have stayed at 250 to 300 micrograms per cubic meter of air, according to the center.

The elderly, children and heart and lung diseases patients are advised to stay indoors.