Why is pluto not a planet anymore?

 why is pluto not a planet anymore? 

Pluto was discovered by clyde tombaugh in 1930. it is not considered a planet anymore because in 2006 Astronomers in IAU ( international astronomical union ) gave a new definition to the word planet.

According to the new definition, a word planet is a celestial body. which is in orbit around the sun, is spherical in shape and it has cleared the neighborhood around its orbit. What does it mean? it basically means that using its gravity A planet should have removed asteroids and dwarf planets, out of its path. thus cleared its neighborhood.

Now, pluto is in orbit around the sun and spherical in shape but since Pluto's neighborhood has many other objects and it has not cleared its neighborhood its not called a planet anymore.