Pulmonary embolism (PE) is a common and potentially fatal condition where blood clots block arteries in the lungs. An estimated 5 million venous thromboses occur annually worldwide, with 10-30% of cases resulting in PE. Risk factors include cancer, obesity, pregnancy, prolonged immobility, and genetic predispositions. Diagnosis involves evaluating symptoms, medical history, imaging tests like CT scans and ventilation-perfusion scans, and blood tests. Treatment focuses on anticoagulation to prevent further clotting and allow natural dissolution, with thrombolysis or embolectomy for severe cases.