Sir, I have passed Diploma in Mech engineering in Aided Polytechnic college. Can I eligible to applied for B.A. Criminology in distance Edu?

Hello Veeraraj, normally speaking yes. Eligibility for any course in graduation is passing of 12th. But you have done Diploma after 10th and hence you have not passed 12th. Right? Don't worry. Diploma is treated as equivalent to 12th. Just go to the institute from where you passed Diploma and demand