How to know whether you are in a clean air zone, how to check if you’ll be charged in the zone or need to create a business account, read further to know the types of CAZs, and all the supported exemptions available. A Clean Air Zone (CAZ) is introduced by some local authorities where a specific set of actions are taken to improve air quality by charging a daily fee for entering the zone. Affected vehicle owners are encouraged to upgrade their vehicles to fit the compliant standards. Until then, Your exceeded emission standard vehicle may have to pay the charge to drive inside the clean air zone. Which cities have clean air zones? Here’s a list of contacts to find out about call charges.