The cheery news last week, probably the loveliest, sunniest of the year, is that Oxford and London are the two worst places in the country for carcinogenic traffic fumes. Traffic pollution is comparable to passive smoking, say researchers, and exposure to traffic fumes greatly increases your risk of lung cancer.

The problem is tiny pieces of matter suspended in the air called ‘particulates’ – and a toxic reddish-brown gas with a sharp smell called nitrous dioxide. Nitrous dioxide causes lung disease.

By far the biggest source of nitrous dioxide in the UK is traffic fumes. And this summer levels of nitrous dioxide in High Street, Oxpens Lane, and St Clements are above levels deemed safe by the EU. The city council is effectively breaking EU law by allowing such high levels of pollution, so it’s good to see them talking up some solutions. But if traffic is giving us cancer, what about urgent action? Like, now.

The researcher who led the study published in The Lancet Oncology advised people to avoid cycling on busy roads. Well I guess that’s one way of looking at it, but in a city where 30 per cent of vehicles on the road are bikes this advice seems rather ill-thought-out. If you look at a map of Oxford, you’ll see there are few ways of avoiding heavily-trafficked corridors such as High Street, St Clements or Cowley Road. If we really are supposed to stop cycling along busy roads to avoid lung cancer, where are we supposed to go? Some back roads provide traffic-free routes, but to access the city centre from the west and the east the arterial roads are mainly unavoidable.

The logical response to this fumes problem is surely not to say stop cycling – and by extension presumably stop walking by these roads and stop living alongside them too? The logical response to this problem is surely to reduce the amount of traffic.

John Tanner, the city councillor with the ‘Cleaner, Greener Oxford’ portfolio, has suggested having electric vehicle-only routes. OK, if buses and (big if) deliveries were all electric this would help, but just look at the streets.

What percentage of vehicles along our busiest, most polluted streets are buses? Maybe 5 or 10 per cent, but the rest are vans and cars, many of them diesel-powered and nearly all of them far filthier than the relatively clean bus engines that the city’s two main operators are running.

It is time that the councils recognised that most people are capable of cycling five miles on urban journeys. We need some judicious road-closures with bollards, or bus gates as on High Street, that welcome bikes and buses through but hold back the choking tide of cars and vans, forcing drivers to make cleaner, greener choices.