By HOU LIQIANG

China has made significant improvement to its air quality in the past five years thanks to continuous government efforts, but air pollution remains an issue because of high emissions, the head of the country's top environmental watchdog has said.

Li Ganjie, minister of ecology and environment, made the comments at a Sunday news conference held to mark the People's Republic of China's 70th anniversary.

The 74 major Chinese cities that turned to the new air-monitoring standard in 2013, for example, saw their average concentration of PM 2.5 particulate matter drop by 41.7 percent over the past six years, he said, adding Beijing experienced an even bigger drop of 43 percent.

He also said the average density of sulfur dioxide in cities above prefecture-level across the country declined from 35 to 14 micrograms per cubic meter last year, down by 60 percent.

The decrease is remarkable with compared with many other countries, he said.

In addition to establishing a regional coordination mechanism for air pollution control, the achievement is also a result of government efforts transforming the structures of industry, transport, energy and land use, he said.

China has managed to achieve extra-low emissions for 80 percent of coal-fired power, he said.

Air quality in the country however is still sensitive to the change of meteorological conditions for pollutant dispersal because emissions remain high, he said.

Meteorological conditions can generally exert an influence of 10 percent to air quality if pollutant discharge remains unchanged.

In some months, the influence can be up to 30 percent in certain cities, he said.

For many cities, good air depends on meteorological conditions, he said.