Hello saryadev.
I am very happy that you asked this question so early, because currently no college has started their counselling yet.
So you have pretty much time to decide. Look there are many ways to join engineering college in India.
So don't worry if you have left some of the entrance exams. Other the common entrance exams, most of the private colleges take their own exams. So you can also go with that.
Other than this if you even don't want to give any exams, then you might have go though management quota, which most of colleges does provide. For that you have to contact admission department of that college. Contact details, you can find on their college web site.
I hope you find a good college and have a great future ahead

Hello,
There's no way.
You have appear for engineering entrance exams in order to get admission in engineering colleges as there are only few colleges that gives admission into undergraduate courses on the basis of class 12th board exams marks.
Good luck.