No, you will be not eligible for NITs but you can take admission in DTU and NSIT through JAC Counselling.

You can consider your state level exam to take admission in government college.

There are some private college as well who consider JEE Main score to take admission in which 75% marks are not required. Below is the list of colleges you can check

Top Private Engineering Colleges through JEE Main

Good Luck!!

No, to get admission in NITs, IIITs, GFTIs you will have to get either 75% or you should be there in top 20 percentile as this is the basic criteria to be fulfilled.

To know about the complete eligibility criteria, you can go through the below link -

Jee main eligibility 2018

Hope this helps!!!