The eligibility criteria for pursuing a B.Tech in Chemical and Pharmaceutical Technology is to pass Class 12 with Physics, Chemistry, and Mathematics as core subjects. Since you mentioned that Mathematics was your fourth subject and you did not pass it,  tis is might be challenging for  eligibility, as Mathematics is usually a mandatory subject for this course.

eligibility criteria can vary, and it's essential to consult the official admission guidelines provided by the university. You can visit the official website of the University of Calcutta or contact their admissions office directly to get the most accurate  information.

Additionally, some universities offer lateral entry options or diploma-based admissions, which might have different eligibility requirements. i would suggest you,  reach out to the university's admissions office.