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.