Sanitation has to do with making things clean, especially by sterilizing.
Have you ever used hand sanitizer to make sure your hands are germ-free? Then you should have an idea what sanitation is: making something clean (sanitary). Sanitation workers pick up your garbage, keeping your neighborhood clean. Sanitation is important in restaurants and also for surgical instruments. You wouldn't want a surgeon to touch you with an instrument that hadn't gone through sanitation, because it would probably have germs.