A senior environmental expert has called for differentiated and tailor-made measures for different regions as the country works to further improve its air quality.

He Kebin, dean of Tsinghua University's School of Environment and a member of the Chinese Academy of Engineering, made the comment on Wednesday at the 2019 Conference on the Innovative Development of the Environmental Protection Industry in Beijing.

He said, despite China's great achievement in air pollution control, the country faces great challenges to further improve air quality.

From 2013 to 2017, the country saw its discharge of sulfur dioxide, nitric oxide and primary fine particulate matter go down by 59, 21 and 33 percent, respectively. It's a period with the fastest decrease rate, He said. 

The Beijing-Tianjin-Hebei province cluster, Yangtze River Delta and the Fenhe-Weihe River Plain area, which are the three key regions for air pollution control, experienced marked decrease of PM 2.5 and PM 10 particulate matter in 2018. While days with heavy air pollution dropped, more cities saw their PM 2.5 density reach the national standard of 35 micrograms per cubic meter, he said.

He said, however, PM 2.5 remains a major pollutant in China. PM 2.5 density in about 56 percent of major Chinese cities is beyond the national standard. The density of the particulate matter is more than 50 percent higher than the standard in almost 19 percent of these cities.

It's a must to take differentiated and tailor-made measures to address the challenges that hinder continuous air quality improvement, considering the differences of cities in their industrial structures and air pollution sources, he said.

He also said measures also should be timely updated in different cities, as pollution conditions tend to change with economic situations and also air pollution control progress.