Smog shrouds Beijing again

Smog shrouded Beijing again on Monday, three days after the city lifted its orange alert for heavy air pollution.

At 8 am, the city's PM2.5 reading exceeded 150 micrograms per cubic meters, according to the Beijing Municipal Environmental Monitoring Center.

The air quality index (AQI) at 27 stations out of 35 in urban Beijing reached Level 5, or heavily polluted, according to the center.

Smog will remain until Tuesday morning, when strong winds are forecasted to clear the sky.

PM2.5 are particles smaller than 2.5 microns in diameter.