A recent report highlighting the damage to aquatic eco-systems caused by highways' run-off will surely spur motorists on to get out of their cars and find less polluting ways to get about.

This run-off includes heavy metals, toxic chemicals and carcinogenic compounds from car tyres, all of which harm human health as well as polluting our waterways, with chalk streams being particularly vulnerable.

One way of reducing this source of pollution would be for new housing developments to be car-free; this may not always be a realistic proposition but could certainly be a planning requirement for brown-field housing developments in urban areas.

Indeed, Portsmouth is again leading the way with work about to start on a car-free 4,000 home development, accessible only on foot, by bicycle and by bus.

In Southampton city centre, new housing developments could also be car free, a proposal which has been supported by the River Itchen's leading ecologist.

The three leading causes of pollution of the River Itchen are agriculture, sewage and highways' run-off and they must all be tackled as a matter of urgency.

We don't, as individuals, have much control over agricultural and sewage pollution but leaving the car at home and choosing to use an alternative mode of transport is something most of us could do, especially when travelling around the city.

Some councils have proposed schemes to "mitigate" the damage caused by highways' run-off but realistically these will take some time to be installed, they may not be effective and in the meantime, aquatic eco-systems will continue to degrade.

There are, of course, numerous other benefits associated with leaving the car at home: better air quality, reduced congestion, safer public realm, reduced demand on the NHS and less damage to road surfaces - in short, a cleaner, greener, healthier, more attractive city.

Lindsi Bluemel
Bitterne Park