The Beijing-Tianjin-Hebei region saw worsening air quality in the first two months of the year, and pollutants from more active industrial production is a major reason, the national environment authority said.

The region and neighboring provinces, including Henan, have been blanketed with air pollution since Tuesday, though air quality in Beijing was improving on Friday.

The region is forecast to have good air quality until at least Monday, the Ministry of Environmental Protection said.

But in January and February, only 44.7 percent of days in the region had good air quality, down 19 percentage points from the same period last year, said Liu Zhiquan, head of the ministry's environmental monitoring department.

Data released on Thursday also showed that indexes for major pollutants in the region soared in the first two months. The average PM2.5 concentration climbed to 111 micrograms per cubic meter, up 48 percent year-on-year.

The national standard for concentrations of PM2.5 - hazardous particulate matter with a diameter less than 2.5 microns - is 35 micrograms per cubic meter.

Nationally, among the top 10 cities with severe air pollution, six cities were in Hebei. Shijiazhuang, the provincial capital, ranked worst of all 74 cities.

Compared with pollution levels in January, air pollution eased slightly in February, with a reduction in PM2.5 concentration, data from the ministry showed.

For example, Beijing saw PM2.5 levels dropping from 116 in January to 71 in February. However, both figures were higher than the same period last year.

"The worsening air quality in some northern regions was mainly because of the disadvantageous weather and growing emissions from industrial production," said Chai Fahe, a researcher at the Chinese Research Academy of Environmental Sciences.

In the first two months of the year, the Beijing-Tianjin-Hebei region has had more windless days and higher humidity, he said, adding that another major reason was more active industrial production, especially thermal power generation, iron and steel, and glass.

"Data showed nitrogen oxide readings in major zones including the Beijing-Tianjin-Hebei region stayed at a high level, indicating there were high emissions," Chai said.

zhengjinran@chinadaily.com.cn