Thick smog shrouded Beijing Tuesday morning, grounding more than 100 flights.

The smog, which the city's environmental protection agency said began at dawn, caused a surge in the density of particulate matter at all monitoring stations across Beijing.

The maximum PM10 (particulate matter under 10 microns) density measured on Tuesday amounted to 560 micrograms per cubic meter of air, the Beijing Environmental Protection Bureau said on its website.

Beijing's weather bureau said the smog reduced visibility to less than 200 meters during rush hour.

Beijing's Capital International Airport said 43 flights were canceled and 80 others were delayed for more than an hour as of 12 a.m.

The smog began to clear after wind speed picked up around midday.

Airport authorities said visibility improved to 2,000 meters around 1 p.m., allowing planes to take off and land.

The neighboring Hebei province was also shrouded in thick smog Tuesday. The provincial weather bureau said the foggy weather hit at least eight cities including Shijiazhuang, the provincial capital. In the worst-hit areas, visibility was less than 50 meters.

Heavy smog also hit central China's Henan province, east China's Anhui, Shandong and Jiangsu provinces as well as Guangdong province and Guangxi autonomous region in the south, creating difficult traffic conditions, the national meteorological station said in a statement.

In Anhui province, three people died and at least 10 others were injured in smog-related collisions and pile-ups Tuesday morning, the local fire prevention bureau said.

The smoggy weather has triggered widespread health concerns, with many pedestrians and cyclists on Beijing's streets seen wearing face masks.

China uses the PM10 standard to measure air quality, but the public has urged government authorities to apply the tighter PM2.5 standard, which measures finer matter that is considered to be more hazardous to people's health.

The Ministry of Environmental Protection said it will factor PM2.5 into national air quality standards by 2016.