Hi aspirent
For getting IIT you  have to first qualify the Jee mains then you have to fight for Jee advance .
This is possible if and only if who are pursuing polytechnic just after 10th pass not after 12th +diploma .
For more information please comment .
Best of luck
Thanks

Yes, diploma holders can get into IITs. You have to write JEE Main and Advance to get into IITs.

You will not be allowed to take addmission through JEE Main in any NIT, GFTI, etc. Its just to qualify for JEE Advance. 

Hello Hariom,
After polytechnic its not applicable to apply for IIT. But if you have done 12th from NIOS with physics and maths, then u can apply for that.