A ZPA (French: Zone de Protection de l'Air) is an area established by the government to improve air quality and reduce the impact of air pollution on public health. These zones are usually established in urban areas or near large industrial facilities or power plants that are considered major emitters of air pollutants. Air protection zones exist in different countries with different characteristics and are also called anti-smog zones.

ZPA zones do not apply permanently, but are only active during bad weather and when air pollution levels are high. In ZPA zones, stricter rules apply to emissions from industrial facilities, power plants, and other large emitters of air pollutants such as transportation. 
These rules are designed to reduce emissions of pollutants such as nitrogen oxides and particulate matter, which are responsible for poor air quality in many cities. These pollutants can affect health, especially the respiratory system and lungs, and can even lead to fatal cardiovascular disease. 

The government regularly monitors and reviews air quality in ZPA zones and, if necessary, takes further action to reduce emissions and improve air quality. This may include wide-ranging bans on certain vehicles, environmental badges, and/or Euro standards.