Is your car green enough?

The Green-Car-Guide says:

"We are viewing a green car as one that is more energy-efficient than average, and/or the manufacturer has made a special effort to develop innovative new technology. An energy-efficient car will save you money on fuel, and save the world’s limited energy resources, and a car with new technology often needs all the support it can get in terms of sales in order to achieve greater mass production, drive the cost of the technology down, and generate revenue to re-invest to make the technology better.Therefore we look at cars that are conventional petrol or diesel, as well as hybrids that use an electric motor in conjunction with a petrol engine, as well as any other vehicles that may be electric or use biofuels for example. "

For low emission cars that works for me, too.