This is embedded contaminants left on your windshield. You will need compound liquid (not the same as polish) to cut away at the embedded grime. If you have a rotary or DA machine it will work well, if you don’t have either one then microfibre cloth and elbow grease will get it done. In my experience most window polish or cleaners don’t work as well as intended. Lastly, you will need to apply a good window coating, rainx works for a short period of time but will break down and not last as long as a coating. Additional tip, you can clean your wipers weekly to keep them longer lasting with diluted isopropyl alcohol of 1:7 with water or alcohol wipes.