Pulmonologist Courses In India: A pulmonologist is a doctor who diagnoses and treats the respiratory system. The respiratory system includes Mouth, Sinuses, Larynx, Pharynx, Trachea, Bronchial Tubes, lungs, and diaphragm. There is a requirement for a pulmonologist when a person has difficulty in breathing, has a continuous cough, smoking-related issues, uneven weight loss, regular coughing up blood or mucus, inconvenience in doing exercise due to difficulty in breathing.