Why is my Audi A7's steering wheel stiff?

I have noticed that the steering wheel of my Audi A7 is becoming increasingly stiff. What could be causing this and how can I fix it?

It is possible that your power steering fluid is low or contaminated. Check the levels and top off or flush the fluid if necessary.

Another possibility is that your steering system's belt is either worn, damaged or needs to be tightened. Have a mechanic inspect and replace if necessary.