The government were taken to court by shyster American layers who declare themselves as “client earth” a so called charity whose sole aim is to make money, they therefore had to call on all areas to have clean air zones, most of which were already, charging for clean air zones was was to be an absolute last resort, but most of them saw it as a first resort, you may drive a caz compliant vehicle and say I’m doing my bit so it won’t affect me - until it is replaced with pay per mile, the whole thing has nothing to do with pollution or clean air it’s all to do with forms of taxation.1. Local councils can not to anything unless parliament has passed legislation allowing them to do so.
2. Parliament decided that CAZs were desirable in areas where the air quality was lower than standards decided by parliament.
3. Local councils are allowed to make proposals for their own areas but they have to be approved by the relevant government minister.
Just because you might not like to believe that because it doesn't suit makes no difference.