Why does the lung scarring take place?

Injury: Any type of injury to the lung, especially chronic, such as bacterial infections, abscess, trauma, can cause scarring.

Lung scars: If damage to your lungs injures the lungs to the point of cell death, then the body will heal by making a scar. Scars do not function well for breathing. Fortunately we have lung reserves. However, if enough lung tissue is scarred then oxygen may be required. If still more damage is done a lung transplant will be necessary.