Most cities in the three Chinese regions with the worst air quality beat their air pollution control targets from October to March, in sharp contrast with their poor performance in the previous heating supply season.

While the novel coronavirus pandemic accounted for part of the improvement, with major emitters cutting back on normal operations, experts said it was also the result of continuous efforts in improving the governance of air pollution.

However, they added, more efforts were needed to transform the smokestack, high energy-consuming industries in the three regions that were the biggest contributors to air pollution.

From October to March, the 80 cities in the three regions－the Beijing-Tianjin-Hebei province cluster, the Yangtze River Delta, and the Fenhe-Weihe Plain in the Yellow River Basin－saw average densities of tiny, PM2.5 particulate matter decline by 14.9 percent year-on-year. They also saw 39 percent fewer days with heavy pollution, the Ministry of Ecology and Environment said in a news release on April 22.

It said only four cities in the regions－Taiyuan and Yuncheng in Shanxi province, Jining in Shandong and Jinhua in Zhejiang－failed to achieve their PM2.5 targets. Yuncheng also missed its goal for the number of days without heavy pollution, along with Dezhou in Shandong, Tianjin, and Suzhou and Huai'an in Anhui.

Shaoxing in Zhejiang province had the biggest reduction in PM2.5 density－28.6 percent－followed by Yangzhou, in Jiangsu, at 26.2 percent.

In the 2018-19 heating supply season, only half the cities in the three regions reached their goals, with most of those in the Yangtze River Delta, and none of the 11 cities in the Fenhe-Weihe Plain met theirs.

Ma Jun, director of the Institute of Public and Environmental Affairs, an NGO, said that based on its monitoring, the pandemic had helped reduce air pollution.

In January, China was seeing air pollution "rebound", he said, but as the virus tightened its grip on the country in late January, the Beijing-Tianjin-Hebei province cluster, for example, generally started to see improved air quality.

"The improvement was especially obvious and even bigger" in March, as the pathogen had a bigger impact on some high energy-consuming industries like cement, Ma added.

Xu Honglei, director of the Transport Planning and Research Institute's environment department, said that from Jan 24 to Feb 2, freight vehicle traffic in Beijing-Tianjin-Hebei province fell by 77 percent compared with before the holiday, and there were 39 percent fewer cars on the roads. Given the pandemic, traffic in those cities didn't return to normal after the break, unlike in previous years.

Ma said continuous efforts by the authorities since 2013 to transform smokestack industries, optimize energy consumption and bolster vehicle exhaust and dust management had "generally resulted in a marked reduction" in discharges.

Ratios of high energy-consuming industries and coal use in the regions remained at a "comparatively high" level, however, and officials should prioritize addressing the problems to bring PM2.5 concentrations below the national standard of 35 micrograms per cubic meter, he said.