Cars drive on and under Guomao Bridge on a heavy hazy day in Beijing January 29, 2013. [Photo/Agenices]

BEIJING - China will make more efforts to reduce PM 2.5 pollutants, as well as other pollutants, a government official said Tuesday.

A national obligatory target will be set to limit PM 2.5 emission, which is a fine particulate matter measuring 2.5 microns or less in diameter, and monitoring and assessing measures will be introduced, Vice Minister of Environmental Protection Wu Xiaoqing said.

Several Chinese cities suffered from dense buildups of smog in January, including the cities of Beijing, Jinan, Xi'an, Shijiazhuang, Zhengzhou and Changsha.

"Both natural and human factors contributed to the lingering smog, including coal burning, pollutant emissions and unfavorable weather conditions," Wu said.

"China will formulate regulations, standards and policies to reduce air pollutants and control coal burning," Wu said.

The government will expedite bans on vehicles that emit large amounts of pollutants, as well as promote more fuel-efficient cars, Wu said.

The ministry said 70 percent of China's cities fail to meet the new air quality standard introduced in February, 2012.