China Huaneng Group Corp, the biggest power generation company in the country, said it will invest about 10 billion yuan ($1.61 billion) this year to upgrade emissions-control equipment, a move to meet the government's requirement for air quality improvement.

By the end of this year, all coal-fired power plants of Huaneng Group will be equipped with desulfurization and dust removal equipment, said Zhao Yi, director of the company's science and technology for environmental protection department.