“Pulmonary fibrosis is a lung disease that occurs when lung tissue becomes damaged and scarred. This thickened, stiff tissue makes it harder for the lungs to work properly. Pulmonary fibrosis worsens over time. Some people can stay stable for a long time, but the condition gets worse faster in others. As it gets worse, people become more and more short of breath.”

MAYO CLINIC (Pulmonary fibrosis – Symptoms and causes – Mayo Clinic)