Why did Pluto fail to retain its planetary status under the 2006 IAU ruling?

Answer

It shares its orbital space with many other significant icy bodies and has not dominated that region

Pluto meets the first two criteria (orbiting the Sun and being round), but it fails the third because it has not gravitationally dominated its orbital region, the Kuiper Belt, which contains many other large objects.

Why did Pluto fail to retain its planetary status under the 2006 IAU ruling?

#Videos

What is a Planet? - Science at NASA - YouTube

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