Hello Ayush

You must get minimum 50 or 55% marks in your class 10 to get admission to diploma course.

Diploma in engineering is polytechnic course.

If you want admission in good engineering college then you must score minimum 75% marks. Your science and maths subjects must be having strong base.

Colleges offering diploma in engineering
Vivekananda Institute,  mumbai
Lovely professional university

Jamia Milia Islamia university

Techno India university

Fees - 13000 to 60,000

Salary - 3 to 4 lakh per annum

For more details you may visit the link given below

https://engineering.careers360.com/articles/diploma-in-engineering