system
Given the following post, respond as if you're commenting on Reddit:
human
What's the best strategy for dealing with windows suddenly fogging up while driving?

My car does not have a defogging setting to my knowledge. (The manual refers to defrost settings).  I can use heat, A/C, recycle air, and change the air distribution (up, passengers, floor, or all 3).  I can also close the passenger vents.  The airflow to passenger vents by the windows can be diverted to a special window vent.
gpt
Fogging is caused by moisture inside the car condensing on a cold windscreen.

Get air blowing on the windscreen - this will evaporate the condensation. Hot air is better, but any air is good. Open the windows to allow the internal moisture out. As long as you're breathing you're increasing the relative humidity inside the car if you don't let the humid air out.