Foreign object obstruction to the airway in the adult usually occurs

Foreign object obstruction in the airway in adults usually occurs during meals due to choking. Airway obstruction happens when there is something that blocks the airway resulting in difficulty in breathing. The most common technique used when a person is identified having foreign object obstruction is called the Heimlich Maneuver. 

"air pollution" is the correct answer i believe

Hyper extension is the extension of a limb/body part beyond its limits