What should I do to pursue a Diploma in fashion designing courses?

First, you have to do intermediate from any recognised college.

10+2 is must to do fashion Design from any college, there are many colleges providing one or two year courses in FD - NIFD, Poornima University, or Poly Technique College.

https://www.shiksha.com/design/fashion-design/colleges/diploma-courses-india Visit the above Shiksha link to know about fees, placements, courses and everything about fashion designing courses. Hope this helps you.