Why does my Audi A1 struggle with acceleration at high altitudes?

I recently took my Audi A1 on a mountain road and noticed that it struggled with acceleration at higher altitudes. I would like to know why this happens and if there are any solutions to improve the car's performance in these situations.

The reduced oxygen levels at higher altitudes can affect engine performance, causing your Audi A1 to struggle with acceleration. To improve performance, consider upgrading to a higher octane fuel or installing a cold air intake system.