> Could you expand on why?

Perhaps I'm a plumber going to work on a house in a LEZ? Perhaps I need to deliver something? Perhaps deliver to the airport (!) inside the LEZ.

There are all kinds of reasons why someone might need to take a van into an LEZ, if you think for more than about quarter a second.

This is primarily a reason why you shouldn't drive a vehicle from the 1970s, as the article suggests, and why LEZs need practicality not to drive service inflation inside the area.

Every emission zone regulation I'm familiar with distinguishes between private and commercial vehicles for exactly this reason. The French zones for example divide vehicles into categories. Private vehicles are set a base category/range, and commercial restrictions are usually the next category looser.