Last month, I took a weeklong trip to the Yellow River's second-largest tributary, the Fenhe River in Shanxi province.

I traveled the Fenhe from its source to the middle and lower reaches before arriving at the point where it flows into the Yellow River.

The water quality of the river, environmental conditions along its length and the appearance of nearby mountains have changed significantly in the past three years.

In 2017, I visited Taiyuan, the provincial capital, for short stays, but the air was thick in particulate matter and the waters of the Fenhe were dark.

Shanxi is known for its rich coal and mining resources, but overdevelopment had taken its toll on the environment.

However, on my latest visit, I saw cities covered in greenery, with new trees planted, grass sown and parks established. Mining sites have been rejuvenated and rivers are flowing freely.

Throughout my stay, the air quality was good and there were blue skies.

I learned from the locals that the environmental improvements were the result of rising awareness, stricter law enforcement and positive action.

As I spoke to government officials and business owners, they frequently used terms such as "sustainable development", "severe punishment", "environmental investment" and "not giving preference to development over the environment".

They referred to President Xi Jinping's trips to Shanxi in 2017 and this year. They also said the provincial government set a goal to prioritize environmental protection in response to Xi's call to build a "beautiful Shanxi" and make the Fenhe River "water-abundant, cleaner and prettier".

Awareness of environmental protection has improved－being passed down from the central government to provincial authorities, and to businesses and local residents.

The provincial government set a goal to improve water quality to Grade V this year at 13 national-level inspection centers monitoring the Fenhe River. This grade is the lowest level on the national five-tier water quality system.

The goal was reached in June, way ahead of schedule.

Meanwhile, the Shanxi People's Congress Standing Committee has announced guidelines for environmental protection in the province for the next three years.

Wang Zhigang, deputy director of the committee's urban construction and environmental protection department, said 43 legislative projects are planned.

This year, Li Guiqin, a television anchor from Shanxi and also a deputy to the National People's Congress, the country's top legislature, proposed harnessing the Yellow River in the province to prevent water loss and soil erosion.

A native of Taiyuan, the provincial capital, Li had witnessed local rivers drying up－envying the clear waters and green mountains whenever she traveled to southern China.

"Environmental protection is so important, as it affects people's lives from all perspectives," she said.

Ji Yongli, executive deputy head of Lingshi county, Shanxi, said the local authority has increased investment for environmental projects, and now that awareness has improved, such work is backed by laws, regulations and financing.

The county has established a sewage treatment network to handle waste from urban and rural areas.

Domestic sewage is the main pollutant in the Fenhe River. However, industrial discharges have now improved, with enterprises severely punished if they ignore environmental protection laws and regulations, Ji said.

She added that although it has been expensive to take such action, the authorities and businesses recognize that it has been necessary to achieve sustainable development.

Since 2009, Shanxi Jinfeng Heat Supply, a privately-owned company in Shanxi, has invested 1.1 billion yuan ($162 million) on restoring Yuquan Mountain－a once-barren area damaged by widespread mining in suburban Taiyuan. The company has planted 5.5 million trees, covering 13 square kilometers.

Sun Zhanliang, deputy head of Yuquan Mountain Forest Park, said the project has yet to make a profit, but has "responded to the government's call to protect the environment".

With increased awareness, stricter laws and regulations, and decisive action, the Fenhe River is now cleaner and Shanxi is gradually shaking off its reputation of being a "polluted province".