From the Qurito FAQ in Help Section:

Why Qurito uses Categories & Tags instead of Topics?

We have introduced Categories to create a better learning experience and order across the platform. Every Category is sub-categorised into Tags. For example, “Computer Engineering” is a branch of “Engineering”. In case your question links to Computer Engineering, you can simply select “Engineering” category and further apply the tag “computer-engineering” in the Tags section in the “Ask Question” page to further classify your question. The true essence, subject or motive of the question can be represented through tags.

You can rather select the category “Countries” and add the tag india. Categories make things more generalised and easily sortable. Tags differentiate within categories.