A man walks along the moat of the Forbidden City in Beijing, China, Feb 21, 2014. A large area of north China including Beijing and Tianjin are experiencing another round of heavy smog and air pollution that is expected to last for a week. [Photo/Xinhua]

Smog will continue to blanket China's north and central regions on Saturday as the the National Meteorological Center (NMC) issued a yellow alert for air pollution.

Beijing, Tianjin and parts of Hebei, Shandong, Henan, Shaanxi and Shanxi provinces expect heavy air pollution from Saturday morning to Sunday morning, according to the NMC forecast.

Beijing, Tianjin and Hebei Province have been suffering heavy smog since Thursday. On Friday, PM 2.5 readings in these regions kept rising and exceeded 200 micrograms per cubic meter, far above the 25 micrograms level considered safe by the World Health Organization.

The NMC on Thursday forecast the smog would last for a week as no cold front is in sight to help disperse it.

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Beijing issues yellow alert for smog