BEIJING, Jan. 8 (Xinhua) -- When photographer Tan Kejun spotted finless porpoises gliding through the waters in the section of the Yangtze River near Xuejiawa in east China's Anhui Province, he knew that the country's longest river was quietly breathing back to life.

"In 2025 alone, I photographed finless porpoises four times, something I had never experienced before," said Tan, a resident of Ma'anshan, an industrial city in Anhui.

Tan has spent three years photographing Xuejiawa, now a lush riverfront greenway. Once scarred by illegal docks and polluting plants, the stretch has become a living testament to ecological recovery.

Sightings of the finless porpoise -- dubbed the "smiling angel" and regarded as a sensitive barometer of aquatic health -- have increased as stricter ecological safeguards take hold and water quality continues to improve.

In the Yangtze, the population of the iconic species increased to 1,249 in 2022, marking a reversal of decades of decline. Meanwhile, 344 native fish species were recorded between 2021 and 2024, 36 more than in the 2017-2020 period, according to official figures.

From resurgent fish stocks to the revival of once-industrial riverbanks, profound changes have swept across the world's third-longest river, since President Xi Jinping introduced a major policy shift for better protection of the Yangtze, revered in China as the "mother river," a decade ago.

Xi, also general secretary of the Communist Party of China Central Committee and chairman of the Central Military Commission, called for promoting well-coordinated environmental conservation and avoiding excessive development at a symposium on advancing the development of the Yangtze River Economic Belt in early 2016.

The Yangtze River Economic Belt covers 11 provincial-level regions from the inland west to the eastern coast, cradling over 40 percent of China's population. Decades of rapid industrialization along the river had powered growth but left deep environmental scars.

A large number of polluting steelworks and chemical plants once lined the banks of the Yangtze, while sand dredging, vessel discharges and untreated sewage accelerated the ecological decline.

The mother river "fell ill, very ill," Xi once lamented, expressing deep concern for the Yangtze's plight.

To reverse the trend, Xi has stressed that restoring the river's ecological environment will be an overwhelming task at present and for a rather long period to come.

The status and role of the river and the economic belt mean the development along the river must prioritize ecology and green development to respect natural, economic and social rules, said Xi at the historic 2016 meeting.

Over the past decade, the Chinese leader has conducted extensive inspection tours along the river and presided over four symposiums on advancing the development of the economic belt.

"We must not allow the ecological environment of the Yangtze River to continue deteriorating in the hands of our generation, and we must leave our descendants a clean and beautiful Yangtze River," he once said.

Concrete actions have been taken. During the past 10 years, nearly 10,000 chemical enterprises have been closed, relocated, or upgraded, and more than 1,361 illegal docks dismantled, according to Wang Changlin, deputy head of the National Development and Reform Commission.

"We do not pursue projects that pose environmental risks, regardless of their profitability," said Yang Peng, chairman of Chuyuan High-tech Group, a dye manufacturer in Hubei.

In 2016, Chuyuan was fined more than 27 million yuan (about 3.85 million U.S. dollars) for discharging excessive pollutants into the Yangtze. It later axed severely polluting lines, built new wastewater treatment facilities and shifted toward greener businesses.

Coordinated conservation efforts include cross-regional joint law enforcement, ecological compensation mechanisms, and the appointment of river and lake chiefs to fight pollution.

To restore biodiversity, China imposed a 10-year fishing ban across key waters of the Yangtze basin in 2021. In the same year, the Yangtze River Protection Law, the country's first basin-specific law, came into effect.

The results have been striking. Water quality in the Yangtze's main stream has remained at Grade II, the second-highest level in China's five-tier system, for six consecutive years.

Efforts should be made to properly deal with the relationship between ecological environment protection and economic development, and explore a new path which puts ecology first while pursuing green development, Xi has stressed.

"When we say there should be no large-scale development, it does not mean we cannot develop it at all," Xi once said. "Rather, we should stay away from destructive development of the river, and we should follow a green development path which puts ecology first."

The economic belt now contributes over 47 percent of China's gross domestic product, up from some 42 percent a decade ago, with roughly one-third of the country's energy consumption.

The economic belt has become a major dynamic hub for innovation and entrepreneurship in the world's second-largest economy.

"Over the past decade, the Yangtze conservation drive has woven environmental protection into the fabric of high-quality development, reshaping the river basin's growth model," Wang Yanxin, academician of the Chinese Academy of Sciences, told Xinhua in a recent interview.