CO2 emission is considered to be one of the reasons for global warming.
One the main contributors is the car.
It turns out to be very easy to lower the CO2 emission of a car by rolling out in neutral gear.
Just take your foot off the gas, gear to neutral and let your car roll out.
You make use of the existing speed and weight (kinetic energy) of your car.
Not only are you reducing the CO2 emission, you also save on fuel costs!
The Petrollo app shows both.