How come they need to introduce 'no idling' zones? Where I live (Norway) idling is banned all over. As far as I know idling for more than one minute is banned

How come they need to introduce 'no idling' zones? Where I live (Norway) idling is banned all over. As far as I know idling for more than one minute is banned all over Scandinavia. Doesn't stop inconsiderate drivers doing it of course. In fact it is already illegal in the UK. Here is a quote from Confused.com: "Stationary idling is an offence under section 42 of the Road Traffic Act 1988," ... The Act enforces rule 123 of the Highway Code which states: "You must not leave a vehicle engine running unnecessarily while that vehicle is stationary on a public road." And doing this can incur a £20 fixed-penalty fine under the Road Traffic (Vehicle Emissions) Regulations 2002.