The CVRAS (Clean Vehicle Retrofit Accreditation Scheme) supports the reduction of air pollutant emissions from older and more polluting diesel vehicles during the transition to a zero-emission fleet.  The scheme was launched in 2017 and funded by Government to accredit retrofit technologies that could reduce levels of nitrogen oxides (NOX) emissions from buses to close to Euro VI levels. The Department for Transport has a requirement for an outsourced service to provide an accreditation scheme. This comprises monitoring performance of the CVRAS bus fleet, improving compliance including telematics reporting, engaging bus operators and Local Authorities on bus fleet maintenance and supporting accurate functioning of Clean Air Zone charging.