Hello Aryan

Diploma course is common name for polytechnic .Those students who want to pursue engineering after x , can go for polytechnic course.

It is convenient for those who have lack of time ( for doing engineering after class xii)

After diploma in engineering students directly get admission to the second year of engineering graduation course.

Here are given a few names of top colleges offering diploma in engineering in India

Aligarh muslim university

Jamia milia Islamia university

IIT madras

Lovely professional university , Jalandhar

For more information you can visit the link given below.

https://engineering.careers360.com/articles/best-polytechnic-courses-after-10th