To ask the Secretary of State for Transport, what assessment she has made of the potential impact of diesel vehicles equipped with defeat devices on levels of nitrogen dioxide pollution in urban areas; and whether she plans to introduce (a) targeted air pollution mitigation and (b) vehicle retirement schemes in areas most affected by non-compliant diesel vehicle emissions.

The Government is committed to reducing air pollution from all forms of transport. Elevated NOx emissions from diesel vehicles contribute to poor air quality.

The Department has not produced a specific UK-only assessment of the potential impact of diesel vehicles equipped with defeat devices on NO₂ pollution in urban areas. However, the Driver and Vehicle Standards Agency’s Market Surveillance Unit (MSU) is investigating cases of possible non-compliant diesel emissions in cars and vans. The investigations aim to ensure any non-compliance found is fixed as soon as reasonably possible, working together with manufacturers to achieve real-world impacts on air quality.

Clean Air Zones have been implemented locally where evidence shows they are the quickest route to reduce NO₂ pollution, and where no equally effective alternatives can be identified. Local authorities are best placed to determine the most appropriate measures to meet legally binding air quality obligations.