Hey Rahul,
Diploma in Mechanical Engineering is a 3-year diploma course that involves application of laws of physics for Design, Analysis and Manufacturing of mechanical systems. Teh eligibility for admission to this diploma course is that you must have passed 10th examinations with minimum 55% aggregate marks from a recognized university.
Fee for this program is Rs. 10000 to 2 lakhs (varies according to different colleges).
Some Colleges offering the course are:

• Lovely Professional University, Jalandhar
• Rameshwaram Institute of Technology and Management, Lucknow
• Dev Bhoomi Institute of Technology, Dehradun
• Chandigarh University, Chandigarh
• Shri Ramswaroop Memorial University, Lucknow
• Ganga Group of Institutions, Delhi

All the best!