Some LCVs now face a charge of £9 per day to enter the centre of Bath, after the city became the first outside London to introduce a clean air zone.
Charges apply 24 hours a day, seven days a week, to diesel-powered pick-ups and vans that do not meet the Euro 6 emissions standard, with the Euro 4 standard required for petrol vehicles.
Charges also apply to non-compliant HGVs and taxis – but private cars are not affected, even if used for work.
Bath and North East Somerset Council says it has received £9.4 million in UK Government funding to help residents and businesses comply with the new measures, and has set up a scheme to help owners of non-compliant vehicles upgrade, to which more than 500 businesses have already applied.
Enforcement is through ANPR cameras installed on roads heading into the zone, which checks vehicles against the database.
Those carrying out non-compliant journeys must declare and pay the charge online, or they will receive a penalty charge notice.
A list of exemptions has been published for some vehicles, such as those used by emergency services.
Council leader Dine Romero said: “We want to reduce NO2 pollution in Bath to within legal limits by the end of 2021 at the latest, and a charging clean air zone is the only way we can achieve this.
“We know this is difficult time for businesses, but we’ve gone ahead with the zone during the pandemic because this is a pressing public health issue.
“However, we are working with residents and businesses to help them replace polluting vehicles with cleaner ones and there is significant financial and practical help available.”