Chongqing — A patrol boat moves through the clear waters of the Yangtze River in Fengjie County, Chongqing. Suddenly, a splash breaks the surface beside the boat — a school of fish appears.

For Yang Yegang, a member of a local fish protection team who spends his days on the river, the scene reflects a decade of ecological change along China’s longest waterway.

"The fish have really come back," Yang said.

The banks of the Yangtze River in Fengjie County, Chongqing, feature clear waters and lush greenery. (Photo/Fengjie County Ecology and Environment Bureau)

Years ago, Yang relied on fishing for a living. He often caught Chinese longsnout catfish, locally known as Jiangtuan. But as water conditions deteriorated, fish populations declined.

The species, scientifically known as Leiocassis longirostris, is highly sensitive to water quality. When the environment worsens, it leaves; when conditions improve, it returns.

The fate of a single fish may seem insignificant, but it has become a measure of the Yangtze River’s ecological transformation over the past decade.

During a recent fish resource survey, Yang and his colleagues discovered Ochetobius elongatus, a critically endangered fish species that had disappeared from the Yangtze River for years.

"It was impossible to describe the excitement," Yang said.

By the end of 2025, monitoring showed that the number of fish species recorded in the Chongqing section of the Yangtze River main stream had increased by 52 compared with before the fishing ban. The Index of Biological Integrity (IBI) for aquatic ecosystems improved by two levels, while rare and endangered species, including the Yangtze sturgeon, Chinese sucker, and rock carp, received stronger protection.

The Yangtze River’s ecological challenges extend beyond the water itself.

The Three Gorges Reservoir experiences annual water-level fluctuations of up to 30 meters, rising to 175 meters during autumn and winter storage periods before dropping to 145 meters ahead of the flood season. The changes create a large water-level fluctuation zone where vegetation must survive both prolonged flooding and drought.

In Wanzhou District, Chongqing, local authorities conducted repeated experiments to overcome the technical challenges of planting trees in the fluctuation zone and successfully cultivated Zhongshanshan, a Taxodium hybrid, at high water levels.

"We repeatedly tested methods to overcome the technical difficulties of planting trees in the water-level fluctuation zone and successfully cultivated Zhongshanshan at high water levels," said Wang Jin, head of the River Management Division of the Wanzhou District Water Resources Bureau.

Today, more than 213 hectares of Zhongshanshan trees line the river in Wanzhou, restoring more than 70 kilometers of shoreline.

The district has also planted more than 1 million bougainvillea plants between elevations of 165 and 175 meters. During dry seasons, the flowers form a "red ribbon" along the river, while grasses planted on low riverbanks help stabilize soil and restore vegetation.

"The roots of vegetation hold the soil in place and make the river water clearer," Wang said.

Birds forage along the Yangtze River in Jiangjin District, Chongqing. (Photo/Jiangjin Media Center)

Chongqing has also strengthened pollution control along the Yangtze River.

The city was among the first regions in China to launch pilot inspections and improvement programs for sewage outlets flowing into the Yangtze River. Among 3,913 sewage outlets connected to eight key rivers and lakes, 3,841 have completed improvement measures, achieving a completion rate of 98%.

The city has also developed the “Bayu Water Management” platform, integrating thousands of data points and tens of thousands of monitoring sensors to track pollution sources and water conditions.

By the end of 2025, water quality in the Chongqing section of the Yangtze River main stream had remained at Grade II for nine consecutive years. All 74 national monitoring sections recorded good water quality for three consecutive years.

The Yangtze River flows through Fengjie County, Chongqing, with lush green riverbanks and clear waters. (Photo/Fengjie County Ecology and Environment Bureau)

The benefits of river protection extend beyond the shoreline.

Above the 175-meter waterline, a green ecological belt stretches along the Yangtze River. The vast orange orchards across the mountains also reduce soil erosion by more than 3,000 tons annually.

More than 1,000 years ago, Tang Dynasty poet Du Fu wrote about Fengjie oranges as being “worth as much as gold.” Today, Fengjie navel oranges remain one of the county’s most important industries.

An orange orchard in Santuo Village, Chongqing, creates a sea of orange trees. (Photo/Ren Jun)

The county’s 25,300 hectares of navel orange orchards support the livelihoods of about 300,000 people. The brand value of Fengjie navel oranges has reached 38.17 billion yuan ($5.3 billion), ranking first among Chongqing agricultural product brands.

In Santao Village, Anping Township, farmers have cultivated navel oranges for more than three decades. The village expanded its orange-growing area from several dozen mu to about 467 hectares, transforming citrus farming into a major source of income.

The ecological recovery of the Yangtze River has also supported other local products, including Wushan red leaves, crispy plums, Huangjing medicinal herbs, lychees, longans and Fuling mustard greens.

The return of a single fish reflects a much larger transformation: a decade of coordinated efforts to improve water quality, restore river ecosystems and create broader opportunities for rural revitalization along the upper reaches of the Yangtze River.