Heavy smog shrouds Beijing on Friday. [Photo/IC]

More air pollution is expected to hit the country this winter due to the effect of La Nina, a climate pattern in the Pacific Ocean, reported Xinhua on Thursday.

Liu Bingjiang, an official at the Ministry of Environmental Protection, said the intensity and frequency of air pollution will likely rise this season due to La Nina.

La Nina is a periodic cooling of the surface of the equatorial Pacific Ocean, which causes abnormal weather patterns.

The beginning of the heating will make the pollution worse, Liu said. According to an earlier report by China Daily, the average temperature this winter is forecast to be 0.5 degrees lower than average.

Inspection groups found that some enterprises in Hebei province have not taken measures to reduce pollution or are emitting pollutants illegally, said Tian Weiyong, another official of the MEP.

Hebei is one of the provinces that are most heavily affected by air pollution. The MEP has urged the provincial environmental protection authority and local governments to punish the violators.

Ten enterprises in Beijing-Hebei-Tianjian area which were caught emitting excessive pollutants in October were shamed in public. Tian said by the end of this year, an online monitoring system will be put in place on chimneys, a major pollution source, in 20 cities in the region.

China has used a series of approaches in recent years to tackle air pollution.

As of September, coal-powered plants with a total capacity of 290 million kilowatts have been transformed to ultra-low emitters, which account for almost one third of the country's total installed capacity. Besides, the country will also phase out 3.8 million heavy-polluting cars this year.

Liu Bingjiang said from January to October, the concentration of PM2.5 in 338 cities across the country dropped by 12.5 percent year-on-year, with the reading for Beijing-Tianjin-Hebei area down 14.5 percent year-on-year.