Pollution in the Huaihe River could rebound without constant supervision, say local environment officials. 

The Huaihe, the country's third longest river, supplies water to some 165 million people in Henan, Hubei, Anhui and Jiangsu provinces in central and east China.

Ten years ago, seeing that the river was heavily polluted, the Chinese Government launched a campaign to clean it up.

While some progress has been made, local environment officials say the river is still very vulnerable.

The latest example was seen in late July. Unexpected rain hit the upper reaches of the river in central China and forced various reservoirs to discharge simultaneously.

As a result, accumulated foul water created a dirty water zone that contaminated the river and rapidly moved downstream.

In Xuyi County, east China's Jiangsu Province, which was one of the worst affected regions, the incident killed 90 percent of the county's aquatic life and caused damages worth 310 million yuan (US$37 million), statistics from local aquatic product bureau show.

"If the water quality in the Huaihe River turns good, our life will become better and better. But if the river continues to be polluted, we will be deprived of our livelihood," said Liu Peiying, a fisherman in Xuyi.

The July spills left Liu with a debt of 700,000 yuan (US$84,000) after the dirty water killed more than 30,000 tons of crabs he bred.

The problem may be worse than just pollution along the river. The economic welfare of residents in four provinces is also at stake.

Local government leaders are often accused of focusing on economic development without regard for environmental protection, said Xu Jiasheng, deputy director of the Anhui Provincial Environmental Protection Bureau. However, economic development is a must.

Xu said the Huaihe River basin flows through poverty-stricken regions along four provinces. In those areas, economic development is the biggest concern.

"The best solution is to balance the relationship between the two," he said.

Environmental protection should be one of the criteria used to judge the performance of government officials and a green GDP (gross domestic products) calculating system should be adopted, he said.

Green GDP is an amendment to GDP that extrapolates the environmental costs of economic development.

Li Jingming, deputy director of the Henan Provincial Environmental Protection Bureau, said industrial infrastructure is crucial to pollution control along the river.

The proportion of such polluting industries as paper making, brewing and tannery, which are abundant in the Huaihe River basin, should be cut down, he said.

A system that ensures the building and operation of sewage treatment plants is also important, said Liu Xiaolei, an official with the Jiangsu Provincial Environmental Protection Bureau.

Statistics show sewage discharged from the local population contributes 60 percent of the major pollutants entering the Huaihe River.

But to build and operate a sewage treatment plant has traditionally cost the government huge amounts of money.

Therefore, Liu said, new funding mechanisms such as BOT (build-operate-transfer) should be adopted. In this formula, a company which invests in and builds a sewage treatment plant will operate the project for certain period of time before it transfers it to the government.