This report presents the results of the work conducted by the Joint Research Centre as the European Commission contribution to market surveillance on pollutant emissions from internal-combustion engine vehicles in 2023. It encompasses experimental data and compliance assessments relative to the measurement of pollutant emissions from internal combustion engine vehicles available on the European Market. The report also contains a short overview of results obtained in the same context between September 2020 and January 2024. It discusses lessons learned during the application of testing procedures, with a view to share best practices with the participating authorities and potentially, to draw the path toward future policy updates. No non-compliances were detected in 2023 for standard laboratory and on-road tests of Type 1 (Worldwide harmonized Light duty Testing Procedure for laboratory emission testing), Type 1a (Real Driving Emission standardised on-road testing) and Type 6 (low-temperature emission testing). The first Type 4 (evaporative emissions) tests since the beginning of the JRC Market Surveillance mandate were performed in 2022 and 2023 in VELA 3, and are reported here.