The Karting World Championship is ruled by the CIK-FIA. It takes place once a year, each year in a different country, and is kart racing's flagship event. Starting 2011, the championship will be disputed on five rounds, each of them in a different country.
In the last few years the World Championship was raced with 100 cc Formula A karts. In 2007, the change in regulations introduced the KF1, 125 cc karts equipped with electric starter, clutch and rpm limiter set at 16,000 rpm, to replace Formula A. The 2010 edition was raced with KF2 karts.
References
Karting World Championship Wikipedia(Text) CC BY-SA