What are CO2 emissions?

CO2 or Carbon Dioxide is a gas emitted by a vehicle when it burns petrol or diesel.Burning a litre of petrol generates about 234 grams of CO2 while burning a litre of diesel produces 270 grams. Despite the fact that burning diesel produces more CO2, a car generally travels further on a litre of diesel than petrol hence diesels are for the most part more environmentally friendly.