Why is the glass unclear and the oil film blurry on rainy days?

[SophiaMarie]

On rainy days, the glass becomes unclear and the oil film appears blurry because, after prolonged exposure to wind and sun, a layer of oil film forms on the windshield. Here is some related information about the oil film: 1. Introduction: The oil film is formed when impurities and exhaust fumes from vehicles in the air enter the pores of the glass over time. 2. Causes: If a vehicle is frequently parked under trees, corrosive substances such as resin, fruit pulp, bird droppings, or insect remains can adhere to the windshield, corroding the glass and forming an oil film. Environmental pollution from parking areas also plays a role; for example, vehicles parked near hotel or restaurant kitchens for extended periods may have oil fumes from cooking adhering to the glass.