BEIJING, Oct. 29 (Xinhuanet) -- China's Central Meteorological Administration has issued yellow alert for heavy smog, the third highest alert, for north and central parts of China. Much of north and central China is shrouded in heavy smog, including Beijing and the provinces of Hebei, Shanxi, Henan.

Weather authorities have warned people in these regions to wear masks and reduce the time spent outdoors.

A sprawling city of more than 20 million people, Beijing saw air pollution levels spike early Monday morning. The smog led to a visibility of less than 500 meters.

The PM2.5 density has hovered around 300 micrograms per cubic meter for the last 24 hours, over 10 times the World Health Organisation’s recommended safe level.

Under the first heavy pollution alert since the city issued its emergency measures one week ago, outdoor activities in schools are to be limited, and factories must reduce emissions.

Heavy pollution has also enveloped neighbouring Hebei province.

In Shijiazhuang, the capital, the morning sun was invisible, making traffic move slower. And many pedestrians wore protective masks.

"Most parts of Hebei are severely polluted, as the conditions over the past day have not allowed the pollutants to dilute." Said Guo Yingchun, spokesperson for Hebei Weather Bureau.

But weather authorities also said the heavy pollution in the region will improve later Monday night, with an upcoming rain.

Vehicle emissions are being blamed for most of the pollution in the region, according to the Ministry of Environmental Protection, with coal-fired plants and factory production taking the rest of the blame.

The government is planning to build a nationwide network over the next 3 to 5 years to monitor the impact of air pollution on people’s health. It’s hoped the data will lead to preventive efforts to reduce PM 2.5 levels.

But it may be a long time before these pictures are a thing of the past.

(Source: CNTV.cn)