A Chinese government report says the number of birth defects in the country has risen by almost forty percent since 2001. Officials are linking the rise to China's worsening environmental degradation, as Claudia Blume reports from Hong Kong.

China's national population and family planning commission says that out of the 20 million babies born in the country each year, up to 1.2 million are born with defects.

This marks a dramatic rise in the number of birth defects in the past few years.

Government statistics do not specify the nature of the problems these children suffer from. But they show that only twenty to thirty percent of the affected infants can be cured. The remaining children die shortly after they are born or suffer their whole life from deformities.

China's northern province of Shanxi has the highest rate of defects. It is also where large coalmines and chemical industries heavily pollute the environment. Officials say there is a link between the increase in defects and environmental factors.

The representative of the World Health Organization in China, Hans Troedsson, agrees, but says more work on the numbers is needed.

"Birth defects can be caused by a number of factors. But of course including those are environmental health risks like different kinds of pollution, which we know," said Troedsson. "What has happened here in China we don't know yet. It could be a combination of different factors - biological factors, chemical factors and also a better reporting system."

The government statistics also show that the number of birth defects is highest in poor, rural areas of China. Troedsson says poor people are more often exposed to health hazards and often have insufficient access to health care.

"Some mothers or mothers-to-be might not have any ante-natal follow up," he said. "Therefore they can miss to be taken care of and maybe to either prevent birth defects or at least having it less severe."

Earlier this year, the World Bank released a report saying that up to 750,000 people die prematurely each year in China due to polluted air and water.