Pneumonia is a lung infection that causes air sacs of your lungs (alveoli) to get filled up with fluids causing severe difficulty in breathing. Apart from the difficulty in breathing, the fluids in the alveoli also result in severe cough, phlegm, high fever, and chills. If left untreated, Pneumonia can cause severe health complications. The impact of pneumonia can range from mild to extremely severe and can prove to be quite fatal if left untreated. Anyone can get affected by pneumonia and this is especially common in children below 2 years and adults above 65 years of age.