China has undergone profound and transformative changes in its ecological environment, with significant improvements in air quality, Minister of Ecology and Environment Huang Runqiu said.

He made the remarks to the media after a plenary meeting of the third session of the 14th National People's Congress at the Great Hall of the People in Beijing on Saturday.

The minister demonstrated the remarkable improvement in the country's air quality with two filter membranes from air quality monitoring facilities in Beijing.

"The one on the left dates back to 2015. It is dark gray because it absorbed a significant amount of PM2.5," he said, referring to particulate matter with a diameter of 2.5 micrometers or less, which are air pollutants particles that can invade even the smallest airways.

"In that year, the PM2.5 density in Beijing stood at 80.6 micrograms per cubic meter, with 46 days of heavy pollution throughout the year," Huang said.

The other, which was gathered last year, was completely different and colored light gray, he said. Last year, Beijing reported an average PM2.5 density of 30.5 micrograms per cubic meter, with one day of heavy pollution.

Huang said the average density of PM2.5 in cities at and above prefecture-level across the country last year reached 30 micrograms per cubic meter, which maintained a generally stable and improving trend.

Compared to 2019, a year before the outbreak of the COVID-19 pandemic, the density decreased by 16.7 percent, he said.

The minister also noted consistent progress in controlling water pollution.

Last year, 90.4 percent of the country's surface water was found with fairly good quality, up by one percentage point year-on-year, he said. It marked the first time that the figure surpassed 90 percent.

China has a five-tier quality system for surface water, with Grade I considered the best. Water with a quality of Grade III is considered fairly good and is suitable for most aquatic organisms to live in.

Huang stressed that high-quality development and high-level protection are not in conflict with each other. Instead, they mutually support and benefit one another.

Since the 18th National Congress of the Communist Party of China in 2012, China's overall economic output has more than doubled, yet its environmental quality has not deteriorated or declined. On the contrary, it has significantly improved, he said.

This served as a true testament to China's effective management of the relationship between high-quality development and high-level protection, the minister underscored.