Why does the Audi A2 have lower fuel efficiency compared to other cars in its class?

I've noticed that the Audi A2 has a lower fuel efficiency rating compared to other cars in its class. Can anyone explain why this is and provide tips on how to improve it?

The Audi A2 has a smaller engine compared to other cars in its class, resulting in lower fuel efficiency. To improve this, try using a higher grade of gasoline and regularly maintaining your car to keep it running smoothly.