BEIJING (Reuters) - China will shut down small-scale “scattered” coal burning in the heavily coal-dependent provinces of Shanxi and Shaanxi by 2020 in the next stage of its war on pollution, a senior environmental official said at a briefing on Wednesday.

FILE PHOTO: People are seen amid heavy fog on the outskirts of Changzhi, Shanxi province March 19, 2010. REUTERS/Stringer/File Photo

Zhao Yingmin, vice-minister of ecology and environment, told reporters that the two northern provinces have been chosen as a key target in the country’s anti-smog efforts over the 2018-2020 period.

Around 90 percent of the two provinces’ energy needs are met by coal, and emissions of hazardous breathable particles known as PM2.5 are second only to the Beijing-Tianjin Hebei region, he said.

“The readjustment of the target zones is a result of comprehensive assessment of the impact of PM2.5 in different regions,” Zhao said.

“Despite tremendous improvements in the Beijing-Tianjin-Hebei region over the last five years, it still ranks as the most polluted,” he added.

After forcing industrial-scale coal users like power plants and steel mills to install technologies to curb emissions, China has already been shifting focus towards what it calls “scattered” pollution sources, including backstreet workshops and rural heating facilities.

China last year completed a groundbreaking action plan aimed at curbing pollution in Beijing-Tianjin-Hebei as well as the Yangtze and Pearl River Delta manufacturing hubs. It is about to publish a new program covering the 2018-2020 period.

Zhao said the Pearl River Delta, which includes the major financial center of Shenzhen near Hong Kong, will not be covered in the new plan, with the region one of the few to reach the interim state PM2.5 standard of 35 micrograms per cubic meter last year.

He said another target zone over the 2018-2020 period would be the far northwestern border region of Xinjiang, a rising coal producer where PM2.5 concentrations have continued to increase.

Experts have called on the government to adopt a more flexible approach to air pollution in the coming years, saying the “one size fits all” policies of the past were no longer effective.

They have also urged China to tackle rising ground-level ozone, known as “sunburn for the lungs” and caused mainly by the interaction of sunlight with vehicle exhaust fumes.

However, Zhao said the country would continue to focus on PM2.5 until the end of the decade.

Average PM2.5 concentrations in 338 monitored cities fell 6.5 percent to 43 micrograms per cubic meter last year. China aims to reach its “interim” national standard of 35 micrograms by around 2035.