BEIJING, Feb. 27 (Xinhua) -- Despite some success in controlling air pollution, China will give no quarter in the battle against pollution, a senior official said Tuesday.

The country is working on a three-year plan to win the battle for cleaner air, focusing on the Beijing-Tianjin-Hebei region and unbalanced industrial and energy structures, Liu Bingjiang, an official with the Ministry of Environmental Protection (MEP), told a press conference.

Under the plan, pollution control targets for some regions will be more demanding than previous requirements, Liu said.

By 2020, cities at the prefecture level and above should experience about 292 clear air days each year, according to an environmental protection conference this month.

A 2013 national action plan on air pollution has achieved the desired results, according to Liu.

The average density of PM 10 in major cities is down 22.7 percent from the 2013 level, Liu said.

Coal consumption in primary energy use fell from 67.4 percent to around 60 percent, more than 200,000 coal-fired boilers were closed and more than 20 million polluting vehicles taken off the roads.

Liu said the situation remained grave as major pollutants remain at high levels. Under the backdrop of global climate warming, factors including the weakening of the East Asia winter monsoon circulation have made the atmospheric flow in the Beijing-Tianjin-Hebei region more stable, increasing the frequency of smog.

On Tuesday, Beijing municipal environmental authority issued a yellow alert for smog, expected to last two days.

Tackling pollution is one of the 'three tough battles" that China aims to win in the next three years.