I am advised by Revenue that used vehicles brought into the State and previously registered using the CO2 format known as NEDC will, from 01 January 2021, be registered based on the NEDC CO2 figure declared on the vehicle registration document issued in the previous jurisdiction with an added calculation to bring that CO2 figure in line with emissions under the WLTP, which was introduced for new vehicles in September 2018. Details relating to the formulae can be found on the Revenue Website at https://www.revenue.ie/en/importing-vehicles-duty-free-allowances/guide-to-vrt/calculating-vrt/calculating-the-nox-charge.aspx