Towards the end of March, we had two days of very high pollution levels in London. The Government's only advice (from DEFRA) was:

Adults and children with lung problems, and adults with heart problems, should reduce strenuous physical exertion, particularly outdoors, and particularly if they experience symptoms. People with asthma may find they need to use their reliever inhaler more often. Older people should also reduce physical exertion.

This advice is aimed at people who are exerting themselves physically (i.e. walking or cycling). Not a word of advice from the Department for Transport to tell drivers not to drive as much. Once again, it's the innocent who are made to suffer whilst the perpetrators causing the problem just carry on regardless!