The NOM-163-SEMARNAT-SCFI-2023, published on January 3, 2024, is Mexico's latest standard regulating carbon dioxide emissions from new motor vehicles weighing up to 3,857 kilograms, including those using gasoline, diesel, alternative fuels, and various hybrid and electric vehicles. This regulation establishes parameters and methodology for calculating target and observed corporate average CO2 emissions (in g CO2/km), sets more stringent emission standards for newer model years, and introduces new credit lines and compensation mechanisms to ensure compliance.