Explain the condition called aspiration pneumonia.?

Aspiration. Aspiration pneumonia occurs when foreign substance (usually vomit) is sucked into the lungs.
Infection in lungs. This is a serious infection caused by breathing in something that is not supposed to be in the lungs, such as food, blood, vomit, or any other foreign matter. This can be a common problem with elderly people who may have had a stroke or some other problem which impairs their ability to cough. People are told not to eat or drink before anesthesia to reduce their risk of aspiration pneumonia.
Inhaled secretions. Aspiration pneumonia refers to a kind of pneumonia that occurs when secretions or vomit are inhaled . This usually occurs when the normal airway protective reflexes are impaired, so in states where there is an altered level of consciousness.