A new system of charging people who park on the streets of Norwich will penalise those who drive large cars.
The cost of permit parking is to rise for the first time since 1993
The city council has said it will introduce a new permit parking scheme based on vehicle length, which is thought to be the first in England.
The council has said the size of a vehicle is directly related to the level of CO2 emissions.
It said it hopes pollution in the city will be reduced and that people will be encouraged to drive smaller cars.
Councillor Brian Morrey said: "We've based the scheme on size and when people apply for their permits they'll have to provide their registration number and this will be checked."
Owners of hybrid vehicles and those which use alternative fuels will be able to park for free.
But critics said the council is generalising and some large cars are cleaner than small, powerful vehicles.
Tony Kimberley, corporate sales manager for Honda in Norwich, said: "Instead of consulting the professionals like myself they've based it on size not CO2 emissions.
"Both the government and the Inland Revenue base everything on CO2."
The new parking charges should be implemented later in the year and will be the first time the cost of permit parking in Norwich has risen since 1993.
Under the scheme people with cars under 3.92m (approx. 13ft) will pay £16 a year, those with cars between 3.92m and 4.45m (approx. 14.5ft) in length will pay £22 and vehicles over that length will incur a charge of £30.