An alarming rise in birth defects was acknowledged by China yesterday, amid concern that heavy pollution is damaging the country’s children.

Babies born with conditions such as cleft palates and extra fingers and toes now account for up to 6 per cent of births each year, according to statistics published yesterday. And the number of babies born with disabilities has increased by 40 per cent since 2001 – a period that has coincided with China’s meteoric economic growth – to between two and three million a year. Up to 12 million more develop defects in childhood.

Officials said that the increase reported by the National Population and Family Planning Commission may, in part, reflect an improvement in the collection of data from rural areas. In addition, families were becoming less reluctant to report defects that in the past had been concealed out of shame.

But there was also evidence that China’s fast-decaying environment was taking its toll. The proportion of babies born with disabilities is even higher in the country’s coal-rich regions, where mining has devastated the landscape and poisoned rivers and valleys.

An Huanxiao, director of the family planning agency in the coal-rich northern province of Shanxi, had few doubts. “The incidence of birth defects is related to environmental pollution. The survey’s statistics show that birth defects in Shanxi’s eight large coalmining regions are far above the national average.”

Li Weixiong, director of the research institute at the commission, admitted that the issue was a concern, but he said that more research was needed to make a clearer link to environmental degradation. China is home to 16 of the 20 most polluted cities in the world.

Mr Li’s commission reported that, nationwide, the rate of defects has increased from 104.9 per 10,000 births in 2001 to 145.5 in 2006. When combined with other visible defects and problems that show up a few months after birth, this figure rises to between 4 and 6 per cent of all births. Of these 30 per cent would die and 40 per cent be disabled. The World Health Organisation estimates that between 3 and 5 per cent of children worldwide are born with birth defects.

The top five birth conditions among Chinese babies are cleft palate, neural tube defects, extra fingers or toes, congenital heart disease and water on the brain. It was not clear which, if any, could be linked to polluted water and air. Mr Li said: “We need time to carry out research on what kind of pollution may lead to which kind of defects.”

The official Xinhua news agency has said that Shanxi, home to four of the most polluted cities in China and a centre of noxious emissions from coke and chemical industries, leads the world for incidence of cleft palates and extra fingers among babies. Poor nutrition and marriage between close relatives in Shanxi are also cited as reasons for the high number of such defects in the province.

Beijing is struggling to improve its air quality before next year’s Olympics and has said that high levels of small particulate matter - sometimes more than three times the recommended level – are a particular concern.

A recent World Bank study showed about 460,000 Chinese die prematurely each year from breathing polluted air and drinking dirty water.

Cause for concern

— China contributes 16 per cent of the world total of carbon dioxide emissions, the second-highest after the US at 22 per cent

— Linfen, in Shanxi province, is the most polluted city in the world. China’s second and third-most polluted cities are also in Shanxi

— Approximately 6,300 babies with birth defects are born in England each year, equivalent to one in every 90 births

— Not all births are monitored, figures are therefore estimates and the ONS acknowledges the possibility of underreporting

— The most common birth defects in Britain are cardiovascular anomalies, talipes (club foot), hypospadias and epispadias (genital abnormalities), cleft lips, cleft palates, central nervous system anomalies and Down’s syndrome

Sources: World Bank; ONS; Times archives

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