Banaras Hindu University

No, plastic engineering is not available in BHU.

Banaras Hindu University (BHU) conducts the BHU Postgraduate Entrance Test (PET) every year for shortlisting the students for admission to 2 years Master of Science (M.Sc Agriculture) programme. The candidates who wish to take admission to the M.Sc Agriculture course at BHU will have to clear the BHU PET entrance exam. The BHU PET 2021 registration process will begin soon.

Both the colleges are good, but BHU is more rated. But it mostly depends on your interest in the subject.

According to eligibility released by IIT JAM in year 2022, all that you need is to have passed the Bachelor's degree programme. Two years gap won't effect. In fact, there are many students who takes more than two years break for IIT JAM preparation. So, yes, you can apply for IIT JAM examination, just prepare well.

There is a separate entrance for B. A EXAMS in the university.

Fees Details
General:
Rs 4.94 K
Course Details
Mode: Full time Duration: 1 Year
PG Diploma in Indian Philosophy and Religion is a full time one year course, and it is offered by Banaras Hindu University, Varanasi. Admission Process
Admissions are made through entrance test. Eligibility Criteria
A candidate who has passed Bachelor degree of 3 years duration relevant stream or equivalent under 10+2+3 pattern from any recognised university.

You can refer to the link given below-
https://www.shiksha.com/university/bhu-banaras-hindu-university-varanasi-23336/cutoff