"This is a target that could be met as long as we work a little bit harder," Zhao Hualin, director of the ministry's pollution prevention department, told a news conference on Wednesday.

The plan also admitted some realistic problems, such as a relatively outdated environmental regulation system, lack of coordination between local authorities and the fact that most cities still lack an air pollution monitoring system.

Meanwhile, a set of concrete plans have been made to meet the air pollution reduction targets. China will further limit the number of industrial programs with high-energy consumption and pollution and further promote the use of clean energy. The consumption of coal energy will also be limited.

Meanwhile, gas pollution will be further targeted in the next three years and high-emission vehicles will be banished from the Beijing-Tianjin-Hebei region, the Yangtze River Delta region and the Pearl River Delta region.

Beijing started releasing PM2.5 data this year and the municipality plans to reduce major pollutant indexes, with PM2.5 falling to 60 micrograms per cubic meter in 2015, from the current level of 70 to 80 micrograms.

Duan Yusen, chief engineer at the Shanghai Environmental Monitoring Center, said it's still unknown whether Shanghai could meet such a target in three years.

"We just started the trial to publish PM2.5 results this June, and by the middle of next year we'll get our first data on the average annual concentration for PM2.5, it's too early to tell," he said.

Shanghai and cities in Jiangsu and Zhejiang provinces started to use a new air quality reporting system on Nov 16 to provide more accurate readings.

The new evaluation criteria takes the results of PM2.5, carbon monoxide and ozone into consideration in addition to figures for sulfur dioxide, nitrogen dioxide and PM10, while the old system monitored only the latter three.