This is a devolved matter and the below information relates to England only. Local authorities already have the power to create clean air zones.
The Government is working closely with those English local authorities where exceedances have been identified to introduce measures to bring forward compliance with nitrogen dioxide limits as soon as possible.
As part of the 2017 UK Plan for Tackling Roadside Nitrogen Dioxide Concentrations, the Government assessed the costs and benefits of introducing a hypothetical national network of clean air zones. This work estimated the total costs to residents and business at £0.5 billion - £2 billion (central estimate £1.2 billion, 2017 prices).
In developing their plans, local authorities are required to carry out a more detailed and localised assessment of the impact of their proposed measures, which may include a clean air zone, on residents and businesses.