Engineering Entrance Exam

Since you have great percentage in 12th, I would suggest you to drop as you don't deserve an average college. Moreover, work hard for it throughout the year and believe that you can make it to that.
Hence, take a drop and work for it.

Last year, the least marks required to get into mechanical were 101 in JEE Mains.
Hence, explore different opportunities.

IEMJEE is only applicable for UEM Kolkata or UEM Jaipur.

Get into one of the NIT's or IIIT's and your life will be successfully with that, along with your hardwork of course.
Moreover, best coding colleges are NIT trichy, Warangal, Surathkal, Rourkela, NIT Jamshedpur, IIIT - D, (IIIT-A and IIIT-H are highly recommended ). and The supremes are IIT's if you can get into ( fingers crossed ) .

No exact answer can be given as admission in SASTRA is on the combined basis of boards and Mains score.
Since you have a low boards percentage, you can only get into it if you have good Mains marks.
However, the branch is non-core, hence the competition will not be much.

Sorry to say but you still have 0.6% less marks than required. Try if you can send it for reevaluation or if something can be done regarding that. Best of luck.

Seems quite difficult as 190 is not a high rank score. Although you should try for it anyway either in another college.