Question to the Department for Environment, Food and Rural Affairs:

To ask the Secretary of State for Environment, Food and Rural Affairs, what assessment he has made of the effectiveness of congestion zone charging in reducing levels of nitrogen oxide.

The effectiveness of both low emission zones and congestion zone charging in reducing levels of nitrogen dioxide (NO₂) has been considered in the ‘Evidence review on effectiveness of transport measures in reducing nitrogen dioxide’ (Defra and Ricardo Energy & Environment, 2016), which is available online at: uk-air.defra.gov.uk.

The UK plan for tackling roadside NO₂ is clear that a range of measures which improve air quality could also reduce congestion, including improving local bus services and changing road layouts at pinch points.