How does the A2 achieve its impressive fuel efficiency?

I've heard a lot about the Audi A2's exceptional fuel efficiency, but can someone break down the specific features and technologies that contribute to this? How does it compare to other cars in its class?

The Audi A2's impressive fuel efficiency can be attributed to its lightweight aluminum body, which reduces overall weight and resistance. Additionally, its aerodynamic design and efficient engine further contribute to its exceptional fuel economy. It sets the benchmark for efficiency in its class.