NANCHANG -- Nearly 1,000 lakes have disappeared over the past 50 years, an average rate of 20 lakes lost each year, said Zhu Guangyao, Vice Minister of State Environmental Protection Administration of China, on Wednesday.

Dead fish and rubbish are seen in a polluted river in Haikou, southern China's Hainan province, September 19, 2006. [Reuters]

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Zhu revealed the figure at the the 11th International Living Lakes Conference held on Wednesday and Thursday in Nanchang, capital of east China's Jiangxi Province.

He said 75 percent of China's 20,000 natural lakes and thousands of artificial lakes suffered from algae pollution caused by an influx of waste water containing nitrogen, phosphorus and other harmful substances.

In central China's Hubei Province, known as the "paradise of lakes", 217 lakes with an area larger than one square kilometer have disappeared since the 1950s when 522 large lakes scattered over the province.

The total size of natural lakes in Hubei had shrunk to 2,438 square kilometers, 34 percent less than 50 years ago.

China has 361,100 square kilometers of lakes and 90,000 square kilometers of wetlands, with a freshwater storage of 226 billion cubic meters.

The major cause of the shrinkage was industrial farming activities, Zhu said, adding the overuse of water and pollution had destroyed water and ecological systems in lake and wetland areas.

The government had set up 160 wetland protection zones and invested heavily in measure to prevent pollution, Zhu said, calling for further efforts by domestic and international organizations.