The windscreen wipers do not wipe clean? What can be the reason for this?

Your answer is correct. Windscreen wipers may not wipe clean if the wiper blades are worn out or damaged, which reduces their ability to clear water and dirt effectively. Additionally, an oil film on the windscreen can cause streaking and prevent proper cleaning, as the wipers cannot remove oily residues. The windscreen heating being defective does not affect the wiping quality; it only helps to defrost or defog the glass. Remember, regularly checking and replacing wiper blades and cleaning the windscreen properly will ensure clear visibility while driving.