Smoking is the most significant risk factor for Chronic Obstructive Pulmonary Disease (COPD). Indeed, approximately 20% to 25% of smokers may develop COPD. However, in the development of COPD, not only smoking but also indoor and outdoor air pollutants play a significant role. Especially in rural areas, indoor air pollutants, such as exposure to smoke from biomass fuels (organic fuels like coal, dung, wood) used for heating with tandoors or fireplaces, pose a significant health threat. Beyond smoking, environmental factors, harmful agents, and genetic predisposition can also be effective in the development of COPD. Regardless of the stage at which the disease is diagnosed, quitting smoking positively affects the course of COPD. Patients who quit smoking can achieve a much higher respiratory capacity compared to when they were only receiving medication. An improvement of at least 10% in respiratory functions is observed within the first two months after quitting smoking.