The lungs produce mucus that serves to keep the nasal cavity and internal passages in the body moist, preventing them from drying out. Additionally, mucus helps filter out dirt and debris to prevent them from entering the lungs.
However, excessive mucus production is also not good for health. If left untreated, it can lead to several serious problems such as bronchitis, wet lungs, pneumonia, and Chronic Obstructive Pulmonary Disease (COPD).