In vehicle regulation, not all “green” standards are created equal. While some focus on reducing air pollutants that harm our health, others directly target the root cause of climate change — carbon dioxide. This factsheet aims to clarify the crucial difference between CO₂ standards and other emission standards, explaining how each serves a distinct purpose and why understanding this distinction matters for effective climate action. CO₂ standards, which limit the carbon footprint of vehicles, are a driving force behind cleaner technologies and a cornerstone of global transport decarbonisation strategies.