Asthma is a chronic (long-term) condition that affects the airways in the lungs. The airways are tubes that carry air in and out of your lungs. If you have asthma, the airways can become inflamed and narrowed at times. This makes it harder for air to flow out of your airways when you breathe out. Things in the environment (called allergens) that affected you as a baby or young child, which may include cigarette smoke or certain germs.