CHANGSHA, Nov. 6 (Xinhua) -- Zhang Jixiang, a 61-year-old environmental volunteer, recalls her hometown in the city of Zhuzhou, central China's Hunan Province, as a place with gray skies, black chimneys, blanched waters and the pungent odor of sewage.

The city was listed as one of the earliest key industrial cities in the 1950s. The place boasts more than 290 "firsts" in China's industrial history, such as the country's first electric locomotive and the first aviation generator.

Although the industrial past with high energy consumption, emissions and pollution brought about an economic boom in Zhuzhou, it has also taken a toll on the local environment.

This former industrial city is now gradually emerging from the heavy pollution mire, driven by a nationwide green development plan to brighten the blue sky, restore the purity of water, and protect the soil quality.

Since 2016, the country has made significant progress in controlling pollution and improving its environment as it pursues a green development path. "Lucid waters and lush mountains are invaluable assets" has evolved into a guideline for China's quest for a greener future through sustainable development.

In 2019, energy consumption per unit of value-added industrial output by major firms dropped more than 15 percent from 2015 -- equivalent to saving 480 million tonnes of standard coal.

"When the air was highly polluted, we didn't even dare to open the windows," Zhang recalled.

Zhuzhou was successively listed as the top 10 seriously-polluted Chinese cities in 2003 and 2004, and swinging to action the city has taken decisive measures to curb emissions from vehicles, enterprises and coal-burning.

Zhuzhou Jiuhua New Material Painting Industry Co., Ltd. is one of the enterprises that was relocated to control emissions. The company had received complaints from neighboring enterprises and residents for several years because of its exhaust gas emissions and pungent smell.

"The workshop is full of dust and the smell of paint is particularly strong," said Yi Zhiping, an employee who has worked in the company for more than 20 years.

In 2018, in response to the call for air treatment, Jiuhua invested 5 million yuan (736,400 U.S. dollars) in collecting and treating organic waste gas emanating from the workshop in different areas. The peculiar smell in the park was replaced by the fragrance of flowers in the green area.

In recent years, the number of days with good air quality in Zhuzhou has increased from 214 days in 2013 to 280 days in 2019. As of Sept. 30, the city had 251 days of fine weather this year, up 33 days from the same period last year.

According to recently released proposals from the Party leadership, China will adopt a series of measures to facilitate the overall green transformation of economic and social development, aiming to further reduce its carbon intensity or the volume of carbon emissions per unit of GDP, and achieve the goal of having CO2 emissions peak before 2030.

In the city's major industrial zone of Qingshuitang, which is often dubbed the Ruhr District of China by locals drawing a reference to the resource-rich German counterpart, 261 enterprises, mostly smelting and chemical plants, clustered in a core area of 15.15 square km.

While the companies paid nearly 50 billion yuan in tax, more than 200 chimneys soaring into the sky have been erected there.

"There was no grass in the place where the water flowed in the past," said Yang Liuqing, who has lived in Qingshuitang for more than 30 years, adding that rice and vegetables planted in the soil would wither in a few days.

In order to completely cut off pollution sources, the city relocated and renovated the industrial zone, shutting down all 261 enterprises by the end of 2018.

Lately, Zhuzhou has started a World Bank loan project to remediate and redevelop contaminated land and implemented a 2-square-km soil remediation project in the core area.

So far, the treatment of 163 of the 262 hectares of land under remediation in the region has been completed.

"It is not only the soil that has been effectively treated, but the once black and smelly water source has also been revived," Yang said.

The city has set up 237 smart electricity meters in its 217 pollution-intensive enterprises to monitor their usage of environmental protection facilities in the plants.

Meanwhile, Zhuzhou has decided not to remove the largest chimney in the city but turn it into an industrial museum.

"People will not forget the city's glorious history of heavy industries, but people should also remember that, only with a good natural environment, can we create a better future," Zhang said.