GUANGZHOU - Guangdong province sounded a battle cry against water pollution problem areas on World Water Day on Thursday.

The provincial environmental protection bureau set the end of the year as a deadline for the city governments of Shenzhen, Dongguan and Huizhou to improve the water quality in Danshui and Shima rivers to Grade V, the minimum standard of usable.

The bureau has raised the alarm about the water quality of the two rivers, which flow through multiple cities, every year since 2008.

Another problem is Shenzhen River. According to the Guangdong environmental report, released on Thursday, the Shenzhen River's water quality falls beneath Grade V, meaning it is heavily polluted, where it runs into the sea.

"The water quality within Shenzhen and the quality of its drinking water sources both meet the standards," said Chen Guangrong, deputy director of the provincial bureau of environmental protection.

According to the report, rivers flowing into Shenzhen from other cities all have substandard water quality.

Huang Ping, dean of environmental science at the School of Environmental Science and Engineering of Sun Yat-sen University, explained about the difficulties about keeping Shenzhen's rivers clear.

"Most of the polluted rivers are short and with less water volume. In consequence, their ability for self-purification is limited," said Huang.

"At the same time, these rivers have to deal with a large amount of sewage."

Shenzhen, a city that has been growing rapidly since the 1990s, has a population of more than 10 million, generating a large amount of domestic sewage.

Aside from the industry in Shenzhen's Longgang and Bao'an districts, the upper reaches of Danshui and Shima rivers are both highly industrialized, and industrial sewage poses special problems.

According to Chen from Guangdong Bureau of Environmental Protection, the Shenzhen government clears sludge from the rivers and pours reclaimed water back into the course.

"These rivers are small, so they don't have enough clear water from the upper reaches to deal with the pollution," Chen said.

(For full story, please see March 24 China Daily, page 3)

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