Is the following sentence correct This is He so much short to such an extent that he reach basin.?

No, the sentence is grammatically incorrect and doesn't make much sense. Here's why:

* "This is He" is incorrect. You should use "This is him" when referring to a person.

* "So much short" is not a standard phrase. You'd say "so short" or "very short".

* "To such an extent that he reach basin" is awkward and unclear. It's better to use a clearer verb like "can't reach" and make the sentence more direct.

Here are some possible corrections depending on what you're trying to convey:

* He's so short that he can't reach the basin. (This is the most likely meaning.)

* He is so short that he needs to use a step stool to reach the basin.

Let me know if you have a different intended meaning, and I can help you write a better sentence.