"The achievements were gained by shifting our emphasis toward developing technology and innovation-driven industries that have higher added value instead of the energy-consuming and environmentally polluting sectors," says Party secretary Mao Xiaoping, who served as the city's mayor during the past seven years.

The city now boasts a number of national and world-leading companies in sectors including renewable energy, bio-pharmaceuticals and integrated circuits. Wuxi-based Suntech Power, for instance, is the world's largest manufacturer of solar cells.

The green sector has also flourished in the city, which is now considered a regional hotbed for China's fledgling environmental sector with the establishment of the Yixing Environmental Protection Science and Technology Industry Garden. With incentives offered by the local government, many startup companies have been able to test waters in the burgeoning green industry and many more high-tech companies have moved in. Their areas include water and solid waste treatment, prevention of air pollution and the development of eco-friendly new materials.

Thanks to industrial restructuring, the city lowered its energy consumption per unit of GDP by more than 20 percent during the 11th Five-Year Plan period (2006-2010) and its levels of sulfur dioxide and chemical oxygen demand, a measurement of water pollution, were reduced by 32 percent, double the national average. The city also pumped 10 billion yuan (1.06 billion euros) in each of the last three years into the protection of water quality. Its wastewater treatment standard is now among the country's highest and 95 percent of domestic sewage is treated.

The algae outbreak in May 2007 in Taihu Lake, shown in this file photo, disrupted water supply to 2 million Wuxi residents for weeks. Zhang Liwei / For China Daily

These and other efforts have led to an exodus of traditional, polluting industries and companies that used to be scattered along the city's waterways as more are forced to move into industrial parks either in or out of the city to refuel their growth.

Among these are Jiangsu Wuxi Steel and Wuxi Coke Chemical Factory. The 50-year-old enterprises have both moved their production facilities to Jingjiang industrial park in Taizhou, northern Jiangsu province, where there are centralized wastewater treatment facilities.

Located within a cluster of residential communities not far from the downtown area, the Wuxi Resin Factory also faces severe limitations on the expansion of its businesses because of environmental and safety concerns. Due to poor infrastructure in the region, the factory does not have access to the sewage pipes that carry its wastewater to the city's treatment plants. It has to invest a huge amount of money annually in the construction and maintenance of self-made wastewater treatment facilities, says Liu Qun, director of the environmental protection department of the company.

"But if we move into the industrial parks of other cities in northern Jiangsu province, where there are centralized wastewater treatment facilities, lower labor and land costs, as well as standardized requirements on safety and environmental protection, we can expect to cut costs while propelling future growth," Liu says.

The factory is slated to complete its relocation by the first half of this year.

Gong Zhiyong, chairman of Bestpac Packaging, a plastic bag manufacturer located in the northern corner of Wuxi, says that although his company is not considered polluting enough to be closed or relocated, he has had a tough time meeting the new environmental standards there.

"It's not just about wastewater treatment. We also have to make separate drainage systems for rain and sewage, and make sure that there is no abnormal smell coming from our factory and so on. If we don't score well on all that, the government has stipulated that we cannot get loans from banks," he says, adding that many manufacturing enterprises in the region failing to meet the requirements have been closed.

For multinational companies like Hynix, one of the largest semiconductor manufacturers in the world, the increasingly stringent environmental standards in Wuxi are in line with its corporate creed of being "environmentally responsible" and have brought real benefits to the company.

The company, located in Wuxi New District, used to recycle each day only 10 percent of its acid-rich wastewater, or 2,300 tons, relying on its own technology and facilities. Yet with the construction of an independent water recycling project supported by the local government in 2007, about 30 percent, or 7,000 tons of effluents, get treated every day and are used again by the company, says Cho Seong-gi, leader of Hynix's environment, safety and health team. "It has greatly reduced our water consumption and protected the environment as well."

Following the algae bloom and in turn, higher standards in wastewater treatment, the company has also been asked to reduce the concentration rates of nitrogen and phosphorus in its wastewater from 40ppm to almost zero, before dumping it into the sewer pipes leading to the city's wastewater treatment plants.

"In an increasingly globalized world, no investors or companies can possibly evade the responsibility of making their environmental behavior and impact transparent," says Bang Chull-won, vice-director of the company's manufacture support group. "In Wuxi where I've lived for so many years, my impression is that local authorities have become quite knowledgeable in terms of environmental protection. And it's obvious that what they are doing is aimed not for short-term but long-term social and environmental gains," he says.