Emissions Analytics Equa ratings
The EQUA Index provides an easy and honest picture of vehicle performance in real-world driving. It puts accurate fuel consumption and air quality data in the hands of the car buyer so they can make an informed decision.
EQUA sets the standard for independent, real-world emissions data based on equipment measuring emissions while cars are driven on the road.
True world emissions ratings
These ratings from the True initiative are based on spot check readings taken at the roadside as vehicles drove past
https://www.trueinitiative.org/true-rating
Air Index ratings
The AIR Index rates cars by the level of harmful NOx emissions they produce from A (the best) to E (the worst) providing reliable comparative results to car buyers and policy makers.