OXFORD city centre will be declared a ‘Low Emission Zone’ on Wednesday in a radical plan to combat worsening pollution problems across the city.

It will mean only buses meeting strict European standards will be able to operate in central Oxford, in a move to improve air quality.

But the tough restrictions will only apply to buses and coaches — and not lorries, vans or other vehicles, as many people had hoped.

And bus companies immediately warned the measures could force them to scrap scores of comparatively new buses, resulting in higher fares for passengers.

Negotiations with bus companies will begin immediately about how emissions can be lowered to create a cleaner city. But local bus firms will be given a 2013 deadline to ensure their fleets fully comply with the stringent, pollution-cutting Euro 5 benchmark.

Oxford City Council has decided it would be too costly and difficult to enforce a ban on all ‘dirty’ vehicles in the city, arguing that buses and coaches are responsible for about 80 per cent of pollution in Oxford.

Oxfordshire County Council is today expected to endorse the city council’s plans to create one of the first Low Emission Zones in a major English city, outside London.

Councillors were told levels of nitrogen dioxide in parts of the city centre now far exceed national air quality objectives.

John Tanner, city council executive member for a cleaner Oxford, said: “Buses are vital to the operation of Oxford but we must reduce those damaging gases and particulates.

“This co-operation between both councils is a breath of fresh air. It will lead to an improvement in air quality across Oxford for residents and shoppers, as well as students and tourists.

“Declaring the city a Low Emission Zone will allow us to set standards and timescales. It is about time that all the companies with buses going through the city centre pulled their weight. The LEZ will make sure they do.

“We expect agreement will be reached with the bus companies that will progressively improve the emissions from their buses. But if that fails we will go to the traffic commissioner and ask him to impose the Euro 5 standard on the bus companies.”

It means bus operators alone will face fines for running pollution-causing vehicles.

The city council says extending restrictions to all types of vehicles would have meant adding to signs and cameras in conservation areas.

County Hall made it clear that ridding the city of dirty buses will be a key objective of its Transform Oxford scheme, which will see significant bus rerouting and much of the city centre being pedestrianised.

The county council will seek to incorporatae the Low Emission Zone into the ‘Quality Bus Partnership’ that it intends to create with bus companies. It is anticipated that this legally-enforceable agreement will bring about joint ticketing and joint timetabling to reduce bus numbers in the city.

Martin Sutton, the managing director of Stagecoach, said: “We support efforts to bring about a cleaner city. But what is being proposed will entail the early scrapping of a large number of buses. There will be a cost associated with this. It raises the question why the proposals do not cover other forms of transport.”

From this autumn, new buses will have to comply to the Euro 5 standards, which stipulate the amount of airborne dirt and nitrogen oxides each vehicle is permitted to emit. But over the last 12 months Stagecoach invested in 48 coaches running in Oxford that were only Euro 4 standard.

Oxford Bus Company already has 42 Euro 5 standard buses, representing a third of its fleet.

A spokesman for the Oxford Bus Company said: “We look forward to working with the council to achieve a deliverable LEZ in Oxford City Centre. But we would have preferred if the standards applied to all vehicles within the defined area.”

The standards also cover coaches and sightseeing buses.

A spokesman for Guide Friday City Sightseeing, which operates ten buses, said none of its fleet complied with the Euro 5 standards.

He added: “At this stage we have had no direct consultation but we would welcome the chance to discuss the issue with the local authority.”