In one year, India's ozone pollution damaged millions of tons of the country's major crops, causing losses of more than a billion dollars and destroying enough food to feed tens of millions of people living below the poverty line. These are findings of a new study that looked at the agricultural effects in 2005 of high concentrations of ground-level ozone, a plant-damaging pollutant formed by emissions from vehicles, cooking stoves and other sources. Able to acquire accurate crop production data for 2005, the study's authors chose it as a year representative of the effects of ozone damage over the first decade of the 21st century.

Rising emissions are causing severe ozone pollution in some of India's most populated regions. Pollution in Delhi, the nation's capital, has reached levels comparable to Beijing, one of the most polluted cities in the world, according to India's Air Monitoring Center.

The main component of smog, ozone at ground level can cause leaf damage that stifles plant growth, injuring and killing vegetation. There are currently no air quality standards in India designed to protect agriculture from the effects of ground-level ozone pollution, according to the new study. Ground-level ozone is formed when nitrogen oxides, carbon monoxide and volatile organic compounds react with sunlight after the chemicals' release from vehicles, industry, or burning of wood or other plant or animal matter.

According to the new study published Aug.14 in Geophysical Research Letters, a journal of the American Geophysical Union, surface ozone pollution damaged 6 million metric tons (6.7 million U.S. tons) of India's wheat, rice, soybean and cotton crops in 2005.

India could feed 94 million people with the lost wheat and rice crops, about a third of the country's poor, according to Sachin Ghude, an atmospheric scientist at the Indian Institute of Tropical Meteorology (IITM) in Pune, India and lead author of the new study. There are about 270 million Indians that live in poverty, according to the study.

Wheat -- one of the country's major food sources -- saw the largest loss by weight of the four crops studied in the new paper, with ozone pollution damaging 3.5 million metric tons (3.8 million U.S. tons) of the crop in 2005. Another major food source, rice, saw losses of 2.1 million metric tons (2.3 million U.S. tons), according to the new study.

Cotton -- one of India's major commercial crops -- lost more than 5 percent of its 3.3 million metric ton (3.6 million U.S. tons) annual output in 2005, costing the country $70 million, according to the new research.