The eligibility criteria are different in all the private colleges according to their rules and norms. 

The National Institute of Open Schooling (NIOS) doesn't cater to the open education system and it seems that it doesn't have value but that's not true. 

Although, in general terms, to get admission to Kongu Engineering College, Erode, you should have at least 50% aggregate in your 12th standard with the subject as physics, chemistry, and maths as the main subjects. At least 45% marks if you fall under the reserved categories (ST, SC, OBC, etc.).