By 2035, China will see a fundamental improvement in the environment, when average PM2.5 levels across the whole country will be lowered to national standards, the country's top environmental protection official said on Monday.

"We are conducting studies to clarify the targets of the fundamental improvement in the environment, but I think, in the fields of air quality, it means the national average of PM2.5 concentration will be lowered to 5 micrograms per cubic meter (the national standard)", said Li Ganjie, minister of environmental protection, at a news conference on the sidelines of the 19th National Congress of the Communist Party of China.

"In some major regions, the average PM2.5 levels should also be lowered to that level," he said, while emphasizing that "it's not easy to reach the targets", as it requires great efforts.

In 2016, the average PM2.5 concentration in 338 cities was 47 microgram per cubic meter, Li said.

PM2.5 refers to hazardous fine particulate matter, whose concentration is a major index to measure air quality.

The Beijing-Tianjin-Hebei region and neighboring provinces have experienced severe air pollution in the past years, especially in autumn and winter, making the heating season in the region a priority for the ministry.

The ministry has introduced strict control measures in the country in accordance with the Action Plan against Air Pollution Control and Prevention since 2013, with more days recorded with blue skies, but still there is a large gap to meet the demands from the public for clean air.

Besides, there are some problems in the process of tackling air pollution, such as the energy consumption mix was not environment-friendly, in which the coal is still the major fuel, discharging pollutants.

But Li said that the environment and meteorological authorities have conducted smooth and close cooperation in air quality forecast services and helped to issue effective emergency responses to tackle air pollution.