Titanium dioxide is a photocatalyst: it’s a material that causes compound responses to happen when the correct sort of light sparkles on it. The correct sort of light for titanium dioxide is bright (UV), the super-blue, high-vitality part of daylight that our eyes can’t see, however, that by the by can give us burn from the sun even on an overcast day. At the point when bright light hits the titanium dioxide covering of a self-cleaning window, electrons are produced. These divert water atoms from the air into hydroxyl radicals that make substance oxidation and decrease responses occur on the covering. In actuality, the hydroxyl radicals assault natural (carbon-based) soil and cleave it up into little pieces that are a lot simpler for the downpour to wash away. Since the responses occur in the titanium covering, on the outside of the glass, they assault the most reduced layers of the soil, extricating encrusted refuse from the glass viably by chipping it away from the back to front.