China leads the world in many environmental sectors as the country strives to promote widespread green transformation, according to a white paper published on Thursday in Beijing.

By the end of 2021, the installed capacity of renewable energy across China was more than 1 billion kilowatts, accounting for 44.8 percent of China's overall installed capacity, according to the document titled "China's Green Development in the New Era" that was released by the State Council Information Office.

The installed capacity of hydropower, wind power and photovoltaic power each exceeded 300 million kW, all ranking the highest in the world, the white paper said.

It said that in 2021, the country's forest coverage ratio reached about 24 percent, and its forest stock volume grew to almost 19.5 billion cubic meters.

"Both figures represented 30 consecutive years of growth, making China the country with the highest growth in forest resources and the largest area of manmade forest," it said.

The white paper also noted that China is the first country to realize zero net land degradation, saying its desertified and sandified areas are both shrinking.

The nation is also making the fastest progress in air quality improvement, it said. The average density of PM2.5 particulate matter in the country's cities at the prefecture level and above dropped from 46 micrograms per cubic meter in 2015 to 30 mcg/cu m in 2021.

In 2021, the output value of China's energy conservation and environmental protection industries exceeded 8 trillion yuan ($118 billion), according to the document.

Zhao Chenxin, deputy director of the National Development and Reform Commission, said the output value of the industries has kept expanding by over 10 percent annually on average in recent years.

"We have the world's largest production scale for clean energy equipment," he said.

He added that in 2021, the total investment China made into clean energy development reached $380 billion, the highest in the world.

Xin Guobin, vice-minister of the Ministry of Industry and Information Technology, China has ranked first in the world in the production and sales of new energy vehicles every year since 2015.