Asphyxia refers to series of symptoms which follow stoppage of breathing and of the heart's action. The main causes are insufficient oxygen in the air, or failure of sufficient air to reach the lungs. It may be the result of drowning, breathing poisonous gases or smoke, some diseases, such as croup, diphtheria, asthma, tumours in the chest, or swelling of the throat due to wounds or inflammation. Blockage or constriction of the respiratory tract by food or other material can also choke and then asphyxiate. Beans, marbles or peas in the nose can suffocate small children. Young children can also be smothered by bed clothes.
Disasters such as avalanches, landslides or mine cave-ins asphyxiate by pressure or by burying people and thus cutting of their air supply. Assault by hanging, garrotting, strangulation or suffocation can also asphyxiate the victim.