Why does the Audi A1 have better fuel efficiency compared to other cars in its class?

I've heard that the Audi A1 has impressive fuel efficiency, what makes this car stand out in this aspect?

The Audi A1 has a smaller and more efficient engine, allowing it to use less fuel while still providing ample power and performance.

Audi has been investing heavily in hybrid and electric technology, which has been incorporated into the A1 to improve fuel efficiency.

The A1 also makes use of lightweight materials and aerodynamic design to reduce fuel consumption and improve overall efficiency.