The local government on Monday announced it would allocate 1 billion yuan (US$146 million) to clean up the Dianchi Lake, one of China's most polluted bodies of fresh water.

In an exclusive interview with China Daily, Kunming Mayor Zhang Zulin said the "Dianchi pollution control project is on top of the city's agenda this year".

"The heavily polluted lake is an eyesore in Yunnan Province, and cleaning it up has been one of the most difficult problems for the country," Zhang said.

This year, the city will focus on "controlling sources of pollution, dredging, diverting other water sources and the ecological restoration of the lake", the mayor said.

Once dubbed "the pearl" of the Yunnan-Guizhou Plateau in southwest China, the Dianchi Lake was known for its crystal clear water decades ago.

However, the country's sixth largest freshwater lake is now covered with a thick layer of blue algae, with an unbearable stink emerging from it.

Almost a third of Yunnan's economic output is concentrated in the drainage area of Dianchi.

Another factor for the heavy pollution is the fact that the population around the lake has increased by more than 2 million in the past 20 years.

To make things worse, almost all of Kunming's domestic sewage is directly discharged into the lake, said Li Kangli, a professor at the Yunnan Normal University.

"And the local water treatment facilities are very poor," he added.

"The radical cure for Dianchi's pollution is to cut off the sources of pollution flowing into it," Li said.

Thirty-five heavily polluted rivers flow into the Dianchi Lake.

The city government has posted 35 officials responsible for treating each of those rivers.

The officials have been patrolling and treating the rivers twice a month since early last year. Five rivers, including the Panlong River, have already been treated, Mayor Zhang said.

Over the past few years, more than 40 percent of waste-water flowing into the Dianchi Lake came from the Panlong River, which is undergoing a overhaul, he said.

Now, the once black and smelly river "has become clearer" after dozens of small factories along the Panlong were shut down and several water treatment plants were put into operation last year.

However, it will be a long time before the 300-sq km Dianchi Lake can be called "the pearl" again, experts said.

Farm lands, factories and residential buildings around the lake need to be relocated to make way for forests and wetland.

By 2020, funds invested in the Dianchi pollution treatment project would have exceeded 100 billion yuan, according to an official involved with the cleanup drive.

In recent years, the central and local governments have attached great importance to cleaning the lake and have spent more than 4 billion yuan on a number of pollution prevention projects built around the water body.

(China Daily March 17, 2009)