A Clean Air Zone (CAZ) is a designated area in a city where measures are taken to improve air quality. These zones aim to reduce pollution from vehicles by encouraging the use of cleaner transportation options. In a CAZ, certain vehicles that do not meet specific emissions standards may be charged a fee to enter or drive within the area. Cities implement CAZs to protect public health and the environment. By limiting access to high-polluting vehicles, such as older diesel cars, authorities hope to lower levels of harmful pollutants like nitrogen dioxide and particulate matter, benefiting residents and visitors alike.