Chronic bronchitis is a type of chronic obstructive pulmonary disease (COPD), which is a group of progressive lung diseases that make it difficult to breathe. It is characterised by inflammation of the bronchial tubes, which are the air passages that carry air to the lungs. This inflammation leads to increased production of mucus and other changes in the bronchial tubes. Chronic bronchitis can significantly impact daily life and, if not managed, may contribute to the progression of COPD.