Lung cancer is the number one cause of cancer deaths worldwide, with over 1.8 million new cases diagnosed in 2012. In India, there are approximately 53,728 new lung cancer cases and 63,759 deaths each year. The main causes of lung cancer are smoking, secondhand smoke, air pollution, and certain occupational exposures like radon gas and asbestos. Symptoms often don't appear until late stages and include cough, blood in sputum, weight loss, chest pain, and shortness of breath. Treatment depends on the stage but may include radiation therapy, chemotherapy, and surgery. The best prevention is quitting smoking and avoiding secondhand smoke exposure.