BEIJING -- Cutting energy intensity was listed as one of the major development goals in the annual government work report delivered by Premier Li Keqiang Thursday.

Quite rare compared with previous government work reports, Thursday's report listed the index, closely related to carbon emission and pollution control, together with gross domestic product (GDP) growth, unemployment rate and consumer price index (CPI).

The major development goals in the government work report had never included an environment index at least in the past decade.

Chinese government plans to reduce the energy intensity, or units of energy per unit of GDP, by 3.1 percent in 2015, lower than the 3.9-percent goal in 2014.

Although previous government work reports had set the target for energy intensity, it has never been placed in such a primary position in the government work report.

Premier Li also pledged to continue reducing the emission of major pollutants.

This year, China will cut the intensity of carbon dioxide by at least 3.1 percent, reduce both chemical oxygen demand and ammonia nitrogen emissions by around 2 percent, and reduce emissions of sulfur dioxide and nitrogen oxides by around 3 percent and 5 percent respectively.

Environmental scientists have long suggested that the low efficiency of energy use has close links with smog that repeatedly troubled China's megacities including the capital.

Zhang Xiaoye, director of an atmospheric composition committee under the China Meteorological Society, said at a seminar last December that excessive use of "unclean" energy, such as coal, is the real culprit of recurrent smog.

Only eight of the 74 major Chinese cities subject to air quality monitoring of PM2.5 met the national standard for clear air in 2014, according to the Ministry of Environmental Protection.

Vice Environment Minister Zhai Qing admitted last month that China's emission cuts are not enough to help improve the environment though having made an "undeniable" contribution.

In Thursday's report, Li pledged to upgrade coal-burning power plants to achieve ultra-low emissions and strive for zero-growth in the consumption of coal in heavily-polluted areas.

The country will promote the use of new-energy vehicles, reduce vehicle exhaust emissions, raise the national fuel quality standard and provide motor gasoline and diesel fuel of higher quality. All highly polluted vehicles registered before 2005 will be banned from the road.

Li also promised to promote clean energy. China will "put great weight" behind the development of wind power, photovoltaic power, and biomass energy, work "actively" to develop hydropower and "stress safety" in developing nuclear power, in addition to exploiting shale gas and coal seam gas.

The year of 2015 is the last year for the government to meet the targets set by the country's 12th five-year national development plan, which includes the reduction of energy intensity by 16 percent and carbon dioxide emission per unit of GDP by 17 percent.

Energy intensity dropped by 4.8 percent in 2014, the biggest in the past few years.