The emission of four major pollutants recorded a year-on-year reduction by at least 2 percent in 2012, Minister of Environment Zhou Shengxian said on Thursday.

Zhou made the statement at a national meeting held here.

Major pollutants include sulfur dioxide, nitrogen oxides, chemical oxygen demand and ammonia nitrogen.

Zhou promised to press for including PM2.5, air-borne particles measuring 2.5 microns or less in diameter, in the country's major pollutant monitoring and measuring system.

This year the country will start monitoring six major pollutant indices, including PM2.5, in 113 cities on the state environmental protection list, he said.

Currently, the monitoring of four national major pollutants as well as PM2.5 and ozone (O3) are conducted in four municipalities, 27 provincial capitals, as well as three key regions -- east China's Yangtze River Delta, south China's Pearl River Delta, and Beijing-Tianjin-Hebei area in the north.

The ministry will also ban vehicles from the roads that were registered before 2005 under exhaust emission requirements, Zhou said, adding that efforts will be made to improve the quality of gasoline and diesel.

To cope with an air quality crisis, contingency measures will be taken, such as suspending or limiting production of certain vehicles, limiting emissions and use of cars, he said.

However, he said that the country is facing a long battle to control PM2.5 intensity.

The ministry aims to reduce PM2.5 intensity in three key regions by 6 percent annually in 2015, he said.

The ministry also set timetables for cities suffering different degrees of air pollution. Cities, where average air pollution is 15 percent higher than the national standard or less, will try to reduce the level to the standards by 2015.

Cities suffering heavy air pollution, which is 30 percent above than the national standard or higher, will try to meet standards by 2030. The cities between the two categories are expected to meet the standards by 2020.