China will strive to optimize its energy mix and industrial structure during the 14th Five-Year Plan period (2021-25) to improve air quality while forging ahead with its ambitious climate targets, a leading environmental official said on Aug 18.

Thanks to consistent efforts by various government bodies, the nation has seen its air quality improve in recent years, Huang Runqiu, minister of ecology and environment, told a news conference.

Last year, the average density of PM2.5 particulate matter across the country reached 37 micrograms per cubic meter, down by 28.8 percent from 2015, he said.

Huang said the improvement has been so great in Chengdu, the capital of Sichuan province, that a splendid scene depicted by Du Fu, a poet from the Tang Dynasty (618-907), is once again visible.

"In my window is framed the snow-capped peak of Xiling Mountain", Du's poem goes. Huang said that he had lived in Chengdu for over three decades and had never seen it.

Xiling Mountain is about 100 kilometers from downtown Chengdu.

In recent years, Huang said he has constantly received photos of the scene from his colleagues and friends or seen such photos on social media platforms. Sometimes, they could even see the snow-capped Mount Gongga, which is even further away.

"This is something tangible to show air quality improvement," he said, adding the average PM2.5 concentration had dropped by about 36 percent in the past five years in Chengdu.

Huang dismissed concerns that air quality improvement last year happened mainly because of decreases in emissions due to the COVID-19 pandemic.

Scientific assessment done by the ministry showed that the pandemic only contributed to an average decrease of 2 mcg/cu m in PM2.5 density last year, he said.

Meanwhile, Huang acknowledged that air pollution control has entered a "deep water zone" with many difficulties and challenges.

"We now need to crack the hard nut, which is our industrial structure and energy mix," he said.

The root causes of China's environmental problems are its high-carbon energy mix and its industrial structure with high energy consumption and carbon emissions, he said.

He said efforts to promote transition in the mix and structure will result in a synergetic effect in pollution control and carbon reduction, considering that they are common sources of many air pollutants and greenhouse gases.

He said new projects with high energy consumption and emissions have been a major target of central environmental inspection teams, which are headed by retired ministerial-level officials and report to Vice-Premier Han Zheng.

The inspections aim to curb ill-regulated development of such projects and get the country onto a track of green, low-carbon and high-quality development, he said.

Huang said China had managed to eliminate solid waste imports by the end of last year, as scheduled. "The time when China was a dumping site for developed countries is gone forever," he said.

The country imported 42.2 million metric tons of waste in 2017, which was reduced to only 8.7 million tons last year before it was completely banned, he said.

Huang said China has been ramping up efforts to improve its domestic recycling system. Last year, 370 million tons of waste were recycled across the country, up by 42 percent from 2016.

He said the ministry will enhance domestic recycling while clamping down on waste smuggling.