Technically speaking, "pneumonia” is the infection and inflammation of the lung tissue or the airways. It could be a, "Lobar pneumonia” where entire lung is involved or "bronchopneumonia” where a bronchus (air tube) and surrounding area may be affected. "Interstitial pneumonia” or, "pneumonitis” is patchy affection of lung tissue. Pneumonia occurs due to droplet infection. Germs expelled from the mouth of the person harboring them are inhaled by the person sitting or standing opposite to him. Development of the disease depends on dose of germs inhaled and resistance of individual. For example a person having less resistance would   develop the illness on very little exposure but a person with good resistance would develop no disease or mild illness after being exposed to the same amount of infecting organisms.Smoking damages the protective inner lining of airways. As a result the individual is more prone to develop pneumonia and that too the severe form. Other respiratory diseases like flu, asthma, chronic bronchitis e.t.c., immune depressed states, alcoholism, are other conditions which increase susceptibility of an individual to develop pneumonia. Exposure to cold weather also increases risk of acquiring pneumonia.  Elderly bed ridden persons are more prone to pneumonia because of reduced body   resistance and impaired ability to bring out expectoration from the mouth.Initially, there may be no symptoms or just malaise, mild cough and chest pain for one or two days. This is followed by high fever.  At this stage, there is excess cough with mucopurulent sputum and even blood. The affected part is very painful. Along with these symptoms, the person develops shortness of breath which adds to the distress and suffering.   The intensity of symptoms varies depending on the type of infecting organism and   their dose. Bacterial pneumonias are usually more severe than others. Pneumonias can also be caused by viruses, fungus and mycobacteria. Chemical pneumonias occur due to inhalation or aspiration of chemicals like petrochemical products.   Diagnosis of pneumonia is suspected on the basis of symptoms and clinical examination and confirmed by X- ray of the lungs. Timely treatment is necessary, to avoid complications.  Infection of the brain is a complication of pneumonia, as germs can travel from lungs to brain via blood.  This can cause paralysis of limbs, convulsions, e.t.c., with or without loss of consciousness.  Abscess can form in lung due to pneumonia.  Coverings of the lungs can be inflamed leading to collection of fluid in lung. In case of severe damage to the lung tissue, working efficiency of that lung is impaired. This leads to difficulty in breathing   on mild exertion, even after recovery.  A person can die due to pneumonia because of respiratory failure. Treatment consists of drugs to relieve the pain and fever and suitable anti infective agents.  Postural drainage is useful in case of copious secretions. Drinking warm water and liquids, inhalation of steam are other measures which are simple to implement and provide immense relief to the sufferer. A person not only suffers physically from such a sinister illness, but also economically in terms of loss of working days and expenses on tests and treatment. A healthy and disciplined life style can do much to prevent pneumonias, by building up the resistance of an individual. Avoiding or giving up smoking is beneficial, because it protects from pneumonia and other respiratory infections. People whose work involves chronic exposure to dust should use protective masks to prevent inhalation of dust.Houses should be kept aerated and exposed to sunlight.   Sunlight kills the germs naturally and good aeration prevents concentration of germs. In case one develops symptoms suggestive of pneumonia, he/she should seek medical treatment at the earliest.