Hello aspirant,

Yes you can write diploma holders like Polytechnic can ready to compose the JEE mains test yet they one thing you should remember that recognition holder will can't almost certainly take the affirmation in NIT/CFTI/IIIT no one but they can probably take the affirmation in IIT through JEE Advance.

So fundamentally JEE mains is the door Inorder to reach at the JEE advance and in the wake of getting into the IIT their affirmation will be considered as the twelfth go out hopeful.

Hope above information is helpful to you 

If you have any queries please let me know 

Thank you