Why is the fuel consumption of the Audi A1 so efficient?

What makes the Audi A1 stand out in terms of fuel efficiency compared to other cars in its class?

The Audi A1 utilizes a highly efficient 3-cylinder engine, along with advanced fuel management technology such as cylinder deactivation and start-stop system, resulting in a lower fuel consumption and emissions.

The lightweight design of the Audi A1, thanks to its use of high-strength steel and aluminum components, contributes greatly to its efficient fuel economy.