Workers busy at a factory in China Photo: VCG

More than 10,000 companies could be exempted or partially exempted from the requirement to reduce emissions during polluted days in northern China in winter, according to an upcoming classification rule from the environment authority.

Companies in 15 key industries such as steel, coking and petroleum will be divided in to A, B and C levels in the Beijing-Tianjin-Hebei region and its surrounding areas.

A-level companies are those which lead in their industries and are models for other companies to look to when upgrading and reconstructing, Liu Youbin, spokesperson of the Ministry of Ecology and Environment, said on Friday during a press conference.

More than 10,000 companies that have advanced producing technologies and highly efficient facilities to tackle pollution will not need to reduce emissions, or will only need to reduce emissions during high-level emergency alerts for air pollution.

The companies are from industries which are newly-developed, strategic or concern people's livelihood.

Coal-fired power plants used specifically for railways will be fully exempted.

Relevant companies will be exempted from halting their production, and supervision will decrease.

The Ministry of Ecology and Environment released a direction for the classification in July.

The final results of the classification will be announced by provincial-level environmental departments.

During the press conference on Friday, the ministry also announced progress on pollution-prevention work concerning soil, underground water, ecology and the environment in rural areas.