Many cities have begun tackling water pollution, buoyed by government cleanup goals and public support for ridding their communities of black, smelly rivers and ponds. But significant work remains, environmental experts say.

"The gap in water quality of major rivers crossing several provinces, such as the Yangtze and Songhua, and small rivers running through cities is wide," said Wu Shunze, deputy head of the Chinese Academy for Environmental Planning under the Ministry of Environmental Protection, on Monday.

While major rivers have seen improved water quality, thanks to growing attention from the authorities in recent years, public complaints about urban rivers continue, he said.

Guangzhou, Guangdong province, for example, has 135 severely polluted rivers, accounting for 58.7 percent of the city's total, while 18 cities in Henan province have 34 black and smelly rivers, more than half of their total.

Serious urban river pollution has drawn attention from the central government. The Action Plan for Prevention and Control of Water Pollution, a pioneering national road map for cleaner waters released on April 16, has set detailed goals for these rivers.

By the end of the year, cities are expected to complete inspections of all polluted rivers, and by 2017, there should be no floating garbage and no illegal sewage discharge. By 2020, all pollution problems should be resolved.

There are some successful cases of cleaning up polluted rivers, such as the Haihe River in Tianjin. Reducing the emission of water pollutants and improving sewage processing technologies have brought clear improvements in river water quality, said Lu Xueqiang, vice-president of the Tianjin Academy of Environmental Sciences.

Efforts to improve the water quality of the Suzhou River in Shanghai that started in 1998 have cost as much as 14 billion yuan ($2.3 billion), Wu said, adding that public attention first spurred the government to solve the pollution.

Public participation has a big role to play in water pollution control, an idea that was shared among environment researchers, experts and officials from China as well as foreign organizations at a forum held on Monday.

Paul Procee, a program leader in China from the World Bank, said the Chinese government needs to harness the power of the public in these efforts, since this has proved effective in other countries.

To enable the public to play a bigger role, the government must strive for a timely release of water quality information, he said.

Contact the writer at zhengjinran@chinadaily.com.cn