COPD is a chronic lung condition characterized by permanently narrowed airways and difficulty breathing. It encompasses chronic bronchitis and emphysema. COPD develops over many years as a result of lung damage, most commonly from cigarette smoking. It causes inflammation and narrowing of the airways and destruction of lung tissue over time. Symptoms include cough, wheezing, shortness of breath, and frequent respiratory infections. Treatment focuses on reducing symptoms, slowing lung function decline, and improving quality of life through medications, oxygen therapy, and smoking cessation.