Design

Hi Rahul,
Both fashion designing and interior designing have equal scope. In the near future, the demand of interior designers and fashion designers in India will increase by 18-20 percent and talking about the salary, it can be 2,50,000/- INR TO 12,00,000/- INR and above depending upon your work experience and PR with architects, builders, and other businessmen and clients and customers.
Interior designing is something which will provide you an opportunity to connect with the world, because there can be a lot of travelling, for a beginning, and later you can create your own setup when you get a good exposure in market.
While, Fashion designing may provide you with an opportunity to start with work at you own home too, you can open up your boutique in a free corner of your home even.
Another important difference between both is that interior designing is something more than just decorating a home or place, but you will also have to catch up with the builders and architects to know about how you will have to plan out for the designs, whereas fashion designing will lead you to practice your knowledge at clothes and fabrics, and their stitching mainly.
And, both the designing paths will give you a chance to enhance your creative skills and management skills, plus will help you earn a good PR (Public Relation) too.
And it will be better if you yourself too do a research about it (as I did, before opting interior designing as further career option), because you yourself know you better than anyone else, and thus, your own research will help you out better.