Luo Qun, deputy secretary of the Party working committee of Nanjing's Jiangbei New Area, which is home to many industrial parks and chemical factories, said effective measures have been taken to tackle chemical pollution in the area.
In 2017, the new area's GDP topped 200 billion yuan, and last year, the figure was 250 billion yuan.
"Environmental protection is one of our most important tasks," Luo said. "We have reduced the area covered by industrial parks from 45 square kilometers to 20 and closed all the factories that didn't meet environmental protection standards.
"We are actively guiding the transformation of chemical parks into new material parks. For example, BASF, a German company in the chemical park, has already made new material products."
Luo added that 42 rivers have been treated and the neighboring environment has been restored. With the improvement of water quality, finless porpoises - aka the "smiling angels" of the Yangtze - have been seen more frequently in the section of the river that runs through Nanjing.
Li Wenqing, chief engineer of the Nanjing ecology and environment bureau, said environmental protection and the restoration of the Nanjing section of the river is a top priority.
"The local government has established 40 key tasks and 55 key programs to reduce production of waste and stabilize the quality of the water in the main stream. By next year, the proportion of bodies of water listed above Grade III should rise by 68.2 percent, while water graded below Grade V, the lowest level in China's water quality system, should be eliminated."
He said local people are encouraged to participate in, and monitor, the protection efforts.
Dongsha Industrial Park, located in Zhangjiagang, Suzhou city, just 4 km from the river, was shuttered in December 2017, reducing chemical oxygen demand by 1,190 metric tons, ammonia nitrogen by 27 tons, sulfur dioxide by 1,530 tons, and nitrogen oxide by 550 tons.
At the same time, hazardous waste was reduced by 2,028 tons and 150,000 tons of standard coal went unused, according to the provincial Ecology and Environment Department.
Guo Jun contributed to this story.