Why was Pluto removed from the planet category?

Create a new category of planet. That should satisfy everybody, as long as Pluto is some type of “planet.” Ceres would be considered a dwarf planet – and Pluto would be considered a dwarf planet (or Pluto/Ceres a double-dwarf planet). And the term could be used for other spherical Kuiper belt objects. read more

The International Astronomical Union (IAU) downgraded the status of Pluto to that of a dwarf planet because it did not meet the three criteria the IAU uses to define a full-sized planet. read more

Pluto is not large enough to have done the latter (i.e. it crosses Neptunes orbit), while all other remaining planets have, so it was downgraded to a dwarf planet. There are now eight planets recognised and five Dwarf planets, of which Pluto is one. read more