Some 600 million people have been affected by the lingering smog since the start of 2013, a report from National Development and Reform Commission revealed.

The report focuses on the grim situation, which has shrouded a quarter of Chinese land in haze since 2013, and looked to energy saving and emissions reduction to ease the problem.

On Tuesday, research published in the Proceedings of the National Academy of Sciences, a US scientific publication, said air pollution from burning coal caused 500 million people in northern China to live, on average, 5.5 years less than the people living in the south.

Liu Zhiquan, an official with the Ministry of Environmental Protection, claimed there was no clear link between coal burning pollution and life expectancy.