To ask the Secretary of State for Transport, how many and what proportion of buses in England have been retrofitted using funding from the Clean Bus Technology Fund since 2015 to September 2019.

344 buses have been retrofitted using funding from the 2015 Clean Bus Technology Fund (CBTF) and to date 1,677 have been retrofitted under the 2017-19 CBTF. There are approximately 35,000 buses in the English bus fleet, meaning around 5.8% of the total fleet has been retrofitted between 2015 and September 2019 through the CBTF. A further 2,793 buses are scheduled to be retrofitted from the most recent round of funding. Many buses are Euro VI or better and are already of a standard that does not require retrofitting in order to avoid Clean Air Zone charges.