Mohali: Smoking has been attributed as the leading cause of lung cancer. Stressing on quitting cigarettes, bidi and hookah, Dr Digambar Behera, Director, Pulmonary Medicine at Fortis Hospital, Mohali, said, “Tobacco smoke can harm lung tissue and affect their ability to inhale oxygen. Tobacco smoke contains carbon monoxide and this gas can limit the oxygen in your blood, thereby decreasing oxygen delivery to the organs.” Passive smokers are also at a great risk of getting their lungs affected. People who are exposed to high levels of radiation, arsenic, chromium, nickel, copper, asbestos etc. also have a high chance of developing the fatal disease, he said.