[gds52]

This is a v common problem with windshields...an oily layer which never gets cleaned up. During rain with continuous wiper action, a white layer is formed which affects visibility.

I found my solution using auto glass polish...for windshield n headlights. Pic below.
Use as per instructions.
After this clean with auto glass cleaner spray.
I also apply this polish lightly on wipers to get the oil layer off from them as well.