Incheon International Airport (IIA) (sometimes referred to as Seoul–Incheon International Airport) is the largest airport in South Korea, the primary airport serving the Seoul Capital Area, and one of the largest and busiest airports in the world. Since 2005, it has been rated the best airport worldwide by Airports Council International every year. It is also rated as the world's cleanest airport and the world's best international transit airport by Skytrax.