Beijing, March 26: China has issued its third major "orange alert" this year, as pollution levels rose up after capital Beijing was named as the country's top city for reducing air pollution last week.

"The orange alert will run from Monday to Wednesday," the Beijing environmental protection bureau said in a post on its Weibo account on Sunday. "The central part of the Beijing-Tianjin-Hebei region is expected to see medium to heavy pollution over the three days," it added.

It is the second smog alert issued for Beijing within this month. Two previous orange alerts were issued in January and March, both of which lasted for three days, The Independent reported. China has a four-tier colour coded pollution warning system, where red is the most severe, followed by orange, yellow and blue respectively.

When an orange alert is issued, all factories in the country such as furniture, cement and other heavy industries are required to reduce their output to 50 percent from 80 percent. Last week, the ecology and environment ministry announced in Weibo that Beijing achieved the biggest reduction in average pollution among 28 cities in northern China from October to February.

In December last year, the Chinese government launched a "massive battleplan" against smog during the winter months, during which pollution usually worsens due to heating.

According to the plan, it included switching households and industries to natural gas from coal for their heating and other needs, as well as compulsory cuts in steel production in the surrounding areas.

The Chinese capital, particularly, has suffered serious air pollution levels for the last many years, produced by exhaust emissions and coal burning from factories in the surrounding regions, accompanied by local construction dust.