Carmakers base their total reported emissions on a number of factors such as the average size of the vehicles, where the cars are driven and the lifespan of vehicles. Carmakers on the whole have used selective data to reach a lower figure.

Carmakers base their total reported emissions on a number of factors such as the average size of the vehicles, where the cars are driven and the lifespan of vehicles. Carmakers on the whole have used selective data to reach a lower figure.