Hebei province will have no days of severely polluted air by 2025 under an action plan rolled out recently by the province's leading group office on air pollution control.

From 2023 to 2025, the number of days with air pollution rated severe or above will be gradually reduced to seven, five and three days, not counting sand and dust weather, Hebei Daily reported the plan as saying.

As home to a lot of heavy industries, Hebei in the past was often shrouded in heavy smog. But the province has made great efforts in the past decade to improve its air quality.

Last year, the average concentration of PM2.5 — a key gauge of air quality that's harmful to human health — was reduced to 36.8 micrograms per cubic meter in Hebei, down by 5.2 percent from 2021, according to the provincial Department of Ecology and Environment.

Days with heavy air pollution in 2022 fell to four, down by five days from 2021, delivering the best air quality since 2013, when records of air quality began to be kept in the province, the department said.

Under the new plan, the control of PM2.5 will continue to be a major task, along with ozone. Autumn and winter will be key periods for taking measures, including industries' structural optimization and adjustments, emissions reduction and diesel-powered truck exhaust control.

It will strictly control the increase of projects that are energy-intensive and polluting, while prohibiting new production capacity in such fields as steel, cement and plate glass.

The province will also vigorously upgrade the rules for factories to make them cleaner, the plan said.