Why Pluto is a dwarf planet??

Do you know why Pluto is a dwarf planet??

There are 3 rules to consider a celestial body a planet.

1. Planet should be spherical in shape with it's own gravity.

2 . Planet should revolve around it's own star / stars.

3 . Planet should clean it's surroundings with it's own gravity.

Pluto does not follow 3rd rule so IAU (International aeronautical union) decided to consider Pluto a dwarf planet.

Facts

There are 5 dwarf planets in our solar system Ceres, Make make, Humea, Eris and Pluto.

Pluto has 5 moons

Thank you