KUNMING -- Southwest China's Yunnan Province plans to spend 8.4 billion yuan (US$1.1 billion) to tackle pollution in Dianchi Lake, the largest freshwater lake on the Yunnan-Guizhou Plateau.

The fund will be used to restore the size of the lake by reversing land reclamation, plant more trees around it and set up sewage treatment plants.

The project will also include the removal of nitrogen and phosphorus from the water with biological means such as planting water weed and putting fish into the lake.

The provincial government would draw up environmental standards even stricter than national rules on pollutant discharges and sewage disposal, said Governor Qin Guangrong.

The province has submitted the spending plan to the central government for approval.

Dianchi Lake remained heavily polluted despite expenditure of 4.76 billion yuan to clean it up in the past decade.

With an area of almost 300 square kilometers, Dianchi Lake, near Kunming, capital of Yunnan, has been diminishing since the 1980s, threatening water supplies in Kunming, with a population of 1.5 million.

"Lack of clean water inflow is the fundamental reason why it is difficult to control pollution in Dianchi Lake," said He Bin, head of Yunnan Provincial Academy of Environmental Science, explaining that only eight percent of inflowing waters were clean.

This year the lake has suffered from blue green algae bloom, suffocating life in the lake and causing it to stink.

Erhai Lake, also in Yunnan, has been cleaned up after a series of measures, including a fishing ban for six months each year since 2004, and treatment of domestic sewage.

Erhai saw blooms of blue green algae in 1999 and 2003.

Blue-green algae outbreaks have been reported in three lakes -- Dianchi, and Taihu and Chaohu in east China -- in the last two months. Last week, water supplies to 200,000 people in Shuyang county in east China's Jiangsu Province were halted for more than 40 hours after ammonia and azote polluted a local river.

Frequent water pollution also raised concern among the central government, as a State Council executive meeting this week stressed the need to amend the existing law on handling of water pollution, allowing for harsher punishment for illegal practices.

Zhou Shengxian, director of the State Environmental Protection Administration (SEPA), said on Thursday that the government China would implement stricter environment rules on the three lakes.

All projects that involve discharges containing ammonia and phosphorus would be banned, and any on-going application to establish such projects would be turned down, Zhou said.