Emissions from diesel engines in the us account for 78 per cent of the total added cancer risk from hazardous air pollutants. This was revealed during an analysis of Environmental Defense, a conservation society. The analysis is based on a us Environmental Protection Agency's study that provides detailed estimates of the levels of 41 top hazardous air pollutants faced by every community in the us . Environmental Defense's website (www.scorecard.org [2]) analyses cancer risks faced by us citizens both at national and local levels. The findings of the analysis are shocking. For example, San Francisco city, that is said to be free from air pollution, shows a risk level of 2,600 additional cancer cases per million, with 90 per cent of the risk coming from diesel emissions.

"The bad news is that the risk of getting cancer due to air pollutants are much higher than what the public was told before. The good news is that a great deal of the air pollution problem can by addressed by focusing on just this one pollutant