Can allergies cause lung congestion as well ?

They call it asthma: Lung congestion triggered by allergies is called asthma. Allergies is one of the 5 major triggers of asthma. The other four are: respiratory infection (especially viral infection, cold air, exercise, and pollution. There are 2 kinds of pollution - outdoor and indoor. Since we spend most of our time indoors that's the more significant. Cigarette smoke is the major indoor air pollutant.