Diploma

Hi Rohit,
It is not bad at all. Diplomas after 10th are considered equivalent to 12th and many programs like Bachelor of engineering allows lateral entry into the second year but these are mostly engineering colleges at state level and not IITs nor NITs. So a lot of factors must be taken into consideration like your competency, career interest, course you want to study, etc.

Yes, you must have passed from a recognized education board with atleast 35% and must have passed mathematics, Science and English. Check Acharya Polytechnic College-Karnataka, Guru Nanak Dev University-Punjab to name a few.

Dear Candidate,
Sure you may apply for Diploma courses, its eligibility is only clear 10th class with minimum 35%.
So, you may apply for the same.

Dear Sanad Saleem,
Go for SAP courses that would be helpful in getting a good job. Choose a course related to your own interest under SAP.
All the best.

LEET examination is being conducted to enter students directly into the the second year of engineering and some of the colleges even take admission based on Diploma percentage.

Well, I would not recommend you to change the college, you should continue with the same college else you will loose two years of your career instead of one.
What was the reason behind your detainment?

A PG Diploma in the desired course is hard to find in Canada. You will find Masters degree mostly in mechanical engineering with automobiles as specialization. You may check the
PGD in mechanical engineering offered by University of Saskatchewan.