Answer the following :

Which planet was removed from the list of 9 planets in 2006?

Pluto is the planet that was removed from the list of 9 planets in 2006. Before that Pluto was also considered as a planet of solar system. But after that International Astronomical Union had given a new definition and characteristics of planet. According to that definition Pluto did not fulfilled all the characteristics that a planet must possess and therefore was removed from the list of 9 planets.

However, we treat it as a member of solar system now also.