Who made the offical decision to downgrade Pluto froma lanet to dwarf planet?

The official decision to downgrade Pluto from a planet to a dwarf planet was made by the International Astronomical Union (IAU) in August 2006. During their General Assembly, the IAU redefined the criteria for what constitutes a planet, leading to Pluto's reclassification. This decision was primarily driven by the need for a clearer definition of planetary status, as more objects similar to Pluto were being discovered in the Kuiper Belt.