Why is my Audi A2 making a squealing noise?

I've noticed that my Audi A2 makes a high-pitched squealing noise when I brake. What could be causing this and how can I fix it?

One possible reason for the squealing noise could be worn brake pads. I recommend getting them checked and replaced if needed. Also, check the brake rotors for any damage.

Another reason could be a loose belt in the engine. I suggest bringing it to a mechanic to have it inspected and tightened or replaced if necessary.