Lung cancer is the leading cause of cancer deaths worldwide. In fact it claims more lives every year than breast colon and prostate cancers put together. People who smoke have the greatest risk of lung cancer though it can also occur in people who have never smoked. According to the World Health Organisation about 80 per cent of lung cancer is due to smoking. As we get ready to observe World Lung Cancer Day on August 1 it becomes imperative that we know how to bring down the risk of this disease. World Lung Cancer Day was first observed in