GAOJIAGOU, China Ten-year old Yilong is already a statistic.
Born at the center of China's coal industry, the boy is mentally handicapped and is unable to speak. He is one of many such children in Shanxi province, where coal has brought riches to a few, jobs for many, and environmental pollution that experts say has led to a high number of babies born with birth defects.
Experts say coal mining and processing has given Shanxi a rate of birth defects six times higher than China's national average, which is already high by global standards.
"They looked normal when they were born. But they were still unable to talk or walk over a year later," said farmer Hu Yongliang, 38, whose two older children are mentally handicapped.
"They learnt to walk at the age of six or seven. They are very weak. Nobody knows what the problem is."
Hu's thirteen-year-old daughter Yimei can only say one word, while her brother Yilong is unable to talk at all. The two spend most of the day playing in their small courtyard, where their mother Wang Caiying tends to their every need and tries to shield them from the neighbors' prejudice.
"I never let them go out, I don't want people to laugh at my children. They stay in this courtyard every day," said Wang, who looks older than her 36 years.
"I am especially worried about my son. He doesn't know how to take care of himself. I have to do everything for him."
The number of birth defects in Chinese infants soared nearly 40 percent from 2001 to 2006, China's National Population and Family Planning Commission said in a 2007 report.
The rate of babies born with birth defects rose from 104.9 per 10,000 births in 2001, to 145.5 in 2006, affecting nearly one in 10 families, the report said.
Infants with birth defects accounted for about 4 to 6 percent of total births every year, or 800,000 to 1.2 million babies, higher than World Health Organization estimates that about 3 to 5 percent of children worldwide are born with birth defects.
"The fact that the rate of birth defects in Shanxi province is higher is related to environmental pollution caused by the high level of energy production and burning of coal," said Pan Xiaochuan, a professor from Peking University's Occupational and Environmental health department. Pan has been doing research into the health effects of pollution in Shanxi for several years.
Neural tube defects were the most common form of defect found in babies in Shanxi, Pan said, though congenital heart disease, additional fingers and toes, and cleft palettes were also common.
China, home to some of the world's most polluted cities, has pledged to cut emissions and clean up its environment, laid waste by decades of breakneck development.
But lax local enforcement and an insatiable demand for energy to feed its booming economy undermine environmental policy goals.
China's ministry of health last week said it would give folic acid supplements to 12 million rural women to try to reduce the rate of defects, especially the neurological defects that are most common and easily prevented with such supplements.
Defects often strike in the poorest families, who can barely afford medical fees let alone care for their children once they reach adulthood.
The meager 10,000 yuan (1,600 US dollars) a year Hu earns transporting goods leaves almost nothing to pay for medical expenses for his two children.
The family's hopes are now pinned on their youngest, a six-month old boy named Yiwu, whose blood tests show he was spared his siblings' afflictions. His parents want Yiwu to be a doctor when he grows up.
Like many other villages in southwest Shanxi, Gaojiagou is surrounded by at least a dozen mines that spew out millions of tons of coal every year to feed China's power plants and steel mills.
Many Gaojiagou villagers suffer from coughs or respiratory illnesses caused by the dust that clouds the air. Their water source has also been polluted by mining, they say.
"Before every family got drinking water from the well in the courtyard," Hao said as water the color of weak tea rushed out of a hose into a metal washbasin. "But now the water in the well is so polluted by the coal mines and washeries around our village, we cannot drink it any more."
(Additional reporting by Jimmy Jian; Editing by Megan Goldin)