The Guangxi Zhuang autonomous region has the dirtiest rivers and lakes and Shandong province spewed the highest amount of sulfur dioxide (SO2).

The Tibet autonomous region remains the country's most pollution-free place without any industrial pollutants and with negligible levels of air and water pollution.

These are some of the findings for last year that the country's top environmental watchdog released yesterday.

The Ministry of Environmental Protection said Guangxi's polluting industries have not only made its rivers and lakes filthy, but also raised its chemical oxygen demand (COD), a water pollution measurement, to the highest at 1.06 million tons.

Thanks to the high concentration of thermal power plants, Shandong emitted more than 1.8 million tons of SO2, making its skies the most choked in the country.

Beijing, as the Olympic Games host city, has reduced its pollution level after years of efforts.

Its SO2 emission and COD both have gone down.

The ministry has blacklisted several cities and power plants for their sluggish and ineffective actions to achieve the central government's green target of cutting major pollutants by 20 percent from 2006 to 2010.

Yingtan in Jiangxi, Sanya in Hainan, Hechi in Guangxi and Yuxi in Yunnan have been criticized for poor wastewater treatment, and penalized by having their approvals of new projects in the cities suspended.

Seven thermal power plants, some of which are branches of the five big power generating groups such as Datang, Guodian and Huadian, have performed below par on SO2 emission control.

The ministry will impose heavy fines on the power plants not fulfilling their commitments and urge them to improve their SO2 reducing technology.

Last year, the power industry cut SO2 emission by 9 percent, while the big five power groups reduced it by 13 percent.

In July last year, the central government decided to set up an accountability system that ties up officials' career with their performance in environment protection and energy efficiency.