Design

IHM is best for hotel managemnet & NID for graphics

You may refer to the article below and accordingly decide the specialisation you wish to get into:
http://www.brazen.com/blog/archive/job-search/7-in-demand-careers-in-design-and-planning/

Dear Kushagra,
You may pursue an online course for fashion designing. Some of the links are mentioned below for your reference:
http://study.com/articles/List_of_Free_Online_Fashion_Design_Courses_Classes_and_Learning_Materials.html

The city does not really matters if you learn pretty well in your graduation and is well aware about the know-how of interior designing. Your skills make you a good or bad interior designer.

You will have to pursue a course in interaction designing.

The city or the state doesn't really matter when you wish to pursue a college, just make sure you have got good colleges there which can provide you with the in depth knowledge about your course and can train you well.

You may refer the link below:
https://design.shiksha.com/fashion-textile-designing-courses-in-kolkata-categorypage-13-69-1-0-0-130-127-2-0-none-1-0

Rohit, Fashion designing is a very specialized field and only those who have a good flair for arts, design, creativity and who are able to imagine, draw nicely can be successful in it. I suggest that you test yourself on these parameters before planning for fashion designing course. BBA you can do surely as it is a different field altogether. You need to apply yourself logically to learn management.