Is it now compulsory to get 75 percent marks in board for general category to give jee mains ?

As per Eligibility criteria for JEE Main and Advanced 2018 it is very much kmportant to score well above 75%.
The criteria is as follows.

1. One must have secured more than 75% marks in Class 12th of their resepctive boards for general category .

2. One can also be from top20 percentile of the board.

3. Candidate should have appeared minimum 5 subjects including Physics, Chemistry mathematics.

However, for SC/ ST category the criteria is relaxdd to 65% only.

One can give improvement exam for Class 12th result in successive years with maximum one attempt.
Candidate can appear for any of subject of his choice or where he failed un class 12th such that total aggregate marks then becomes 75% or more.

To check more details, go for official notification given below.

https://www.google.co.in/amp/s/m.timesofindia.com/home/education/cbse-improvement-exam-2018-application-form-released-fill-now/amp_articleshow/61271827.cms

All the best.

Definitely. Otherwise aap quality v Kar jao mains Mein tabbhi you will not able to take part in JOSAA counselling

Yes it is compulsory to get 75 percent in board exams