Beijing has developed measures to cut fine particle pollution or PM 2.5 in the air during the 2012-2020 period, local authorities said Monday.

As vehicle exhaust accounts for 22.2 percent of the total emissions of PM 2.5, fine particulate matter 2.5 microns or less in diameter, Beijing attaches great importance to the development of public transportation and by 2015, a total of 660 km of metro lines should be in service, said Zhang Gong, head of the municipal Development and Reform Commission.

A subsidy scheme will also be issued to encourage consumers to buy new energy vehicles, Zhang said.

In addition, the city aims to cap its annual coal consumption at 15 million tonnes by 2015, by replacing coal used in coal-fired power plants with natural gas, Zhang said.

At present, the coal consumption of coal-fired power plants in Beijing is 8.8 million tonnes a year.

Beijing has disclosed the amount of PM 2.5 in the city's air since January. The PM 2.5 gauge is considered stricter than Beijing's previous standard of PM10, as it monitors fine particles 2.5 microns or less in diameter.

According to the Beijing work plan on air pollution control released earlier this year, the city will cut PM 2.5 levels by 15 percent by 2015 compared with 2010 levels, and cut overall air pollution levels by 30 percent over the same period.