According to a new study, China's coal policy has attributed to reduce 5.5 years of life expectancy. China has a policy of giving free coal to its residents in the north. The study has revealed that air pollution, a result of burning coal in the area north of the Huai River, has gone up by 55% than in the south. The north has the population of some 500m people.

The policy has also attributed to increasing number of rates of heart and lung disease. The policy came in existence in 1980. The study was a collaborative result of researchers from China, the U. S. and Israel.

The researchers studied pollution and deaths in 90 cities in the north and south from 1981 to 2000. They found increase in a type of pollution called total suspended particulate. It is found in soot and smoke.

Mortality statistics were also analyzed by the researchers in 1991-2000. They found evidence of decline in life expectancy years in areas that were previously coal free. The study was published in the Proceedings of the National Academy of Sciences.

The study said, "The analysis suggests that the Huai River policy, which had the laudable goal of providing indoor heat, had disastrous consequences for health".