Question

why is Pluto no longer considered a planet give reasons for your answer

Answer 1

Some of the objects may crash into the planet, others may become moons. Pluto follows the first two rules: It is round, and it orbits the sun. It does not, however, follow the third rule. It has not yet cleared the neighborhood of its orbit in space. Because it does not follow this rule, Pluto is no longer considered a planet.

Answer 2

pluto is not considered as the planet of the solar systems because in 2009 when some organisation such as ISRO and NASA  describe some properties of planets so pluto does not match the characteristics which they had introduced 

so, finally pluto is no longer considered as the planet