Why is the Audi A2 considered a contender for the most aerodynamic car in its class?

I have heard that the Audi A2 was designed to have a low coefficient of drag, but I'm wondering what specifically sets it apart from other cars in its class. Are there any particular features or design elements that contribute to its aerodynamic performance?

The Audi A2's unique, streamlined shape and flat underbody contribute to its impressive drag coefficient of just 0.25.

The A2's lightweight aluminum construction also plays a significant role in its aerodynamic abilities, as it allows for a more efficient power-to-weight ratio.

In addition to its design and materials, the A2 also utilizes advanced technology such as active grille shutters and aerodynamic wheel covers to minimize air resistance and improve fuel efficiency.