Last year it was reported in the Norwich Evening News that the average levels of dangerous nitrogen oxide pollution in parts of Norwich exceeded those of London, with the main offenders being buses and coaches.

The areas mentioned included Riverside, St Stephens, Prince Of Wales Road, Newmarket Road and Castle Meadow, with Castle Meadow being the worst offender.

No surprises there since in any city or town centre there are going to be high levels of pollution on the main traffic arteries, especially at peak times due to slow moving (and stationary) vehicles.

With improvements in engine design the levels of pollution being emitted from diesel engines are slowly coming down.

Some of these vehicles are already on our roads, but realistically, a major improvement under these traffic conditions is unlikely any time soon.

Buses and coaches in St Stephens and Castle Meadow can be dealt with far more successfully, without cost and drawn out meetings to discuss what to do.

At present, at any time, there can be 10 or more buses or coaches stationary in Castle Meadow or St Stephens with their engines running, with passengers who will be boarding or alighting.

When the bus comes to a standstill at the bus stop then the first thing the driver should do is to switch off his engine and not switch it back on until he's ready to depart.

Not only would this help in reducing pollution, it would also save on fuel costs.

It already happens at The Norwich University Hospital, so why not here?

This will provide a cleaner environment for waiting passengers and for the number of pedestrians who use these main city streets (along with the many tourists).

No longer will they have to breathe in high levels of diesel fumes and will, for the first time in many years, actually enjoy walking in one of the city's most beautiful areas — Castle Meadow.

On the subject of Castle Meadow and St Stephens, why do buses and taxis drive at a speed which does not take into consideration the high level of pedestrians?

Do we need a serious or fatal accident before something is done?

It appears that the 20mph speed limit does not apply to St Stephens or Castle Meadow.

Charles Almond, Culverin Close, Thorpe St Andrew.