BEIJING A new Chinese government survey of the country's environmental problems has shown water pollution levels in 2007 were more than twice the government's official estimate, largely because agricultural waste was ignored.
The data, presented by Vice Environment Protection Minister Zhang Lijun, revives persistent questions about the quality of Chinese official statistics and the effectiveness of a government push for cleaner growth after decades of unbridled expansion.
The first national census on pollution sources found that discharge of "chemical oxygen demand" (COD) -- a measure of water pollution -- in wastewater was 30.3 million metric tons, Zhang said.
The government had said in an official paper published two years ago that 2007 was the first year it managed to reduce water pollution, with COD falling 3 percent to 13.8 million metric tons.
The census has been years in the making, in part because it was extremely comprehensive, but possibly also because the contents include painful revelations like this one.
Zhang played down the difference between the totals. He said it was explained by the survey's expanded scope, the inclusion of agricultural sources of wastewater -- which contributed some 13.2 million metric tons -- and different calculation methods.
"The scope of the data was different, this time it included a survey of agricultural sources," Zhang told a news conference.
A more detailed survey of industrial and household emissions, and a different statistical approach also contributed to the leap. When these were accounted for, COD was only around 5 percent above the original 2007 figure, he said.
Figures for other pollutants did not suggest widespread fiddling of data. Acid-rain-causing sulfur dioxide emissions for example, were pegged at 23.2 million metric tons by the census and had been estimated at 24.7 million metric tons in the earlier data.
But whether the omission of agricultural pollutants was intentional or not, the fact that the government managed to overlook a major contributor to one of its benchmark pollution indicators is bound to raise concern.
MORE DATA NOT RELEASED
There may also be other serious problems that Beijing is reluctant to reveal. Activists who welcomed the effort to collect a more comprehensive picture of the country's pollution problem, also called for access to detailed results.
"It appears that the comprehensive pollution data from the census has not been made accessible to the public," Greenpeace Campaign Director Sze Pang Cheung said.
"We urge the government to immediately establish a strong platform through which the public could easily access a wide range of pollution data."
Zhang said the survey had given China a better handle on its challenges and the country in future would hope to increase the range of pollutants it monitored and controlled.
It was a sign of China's commitment to shifting its economic model, he added, which should allow it to cap pollution growth at an earlier stage of development than western nations.
"Because China has taken a different development path than other advanced nations, it is very likely that the peak of our pollution will come (earlier)," he said.
But he added that the government would not change the baseline or survey methods for a target of cutting wastewater pollution 10 percent by 2010 from 2005 levels.
"The emission reduction base was determined on the basis of 2005 environmental data, and so the targets...have to remain the same," he said.