Low Emissions Zones have their place in cleaning up the UK's worst air pollution hotspots, writes Richard Howard. But we also need to adopt fiscal measures to encourage a shift away from diesel vehicles, at once delivering cleaner air, increased tax revenues, and lower carbon emissions.If we are to clean up air pollution in London and the rest of the UK, then Government needs to recognise that diesel is the primary cause of the problem, and to promote a shift away from diesel to alternatives.There is an air pollution crisis taking place in London and many of the UK's other major cities.