Hey,

Yes you may pursue ma in economics even not doing graduation in economics. The minimum eligibility criterion required for a Masters degree is 50% aggregate in Bachelor’s degree in any discipline.

But note that some colleges do ask for Economics people only for admissions in ma in Economics. Basically it differs from college to college. 

Admission to M.A. Economics is offered by many colleges and universities all over India generally through entrance exams for the full-time course. However, open universities like IGNOU provide admission on merit basis. 

Hope this helps.