Following is list of top colleges offering BSC IN economics-
-St stephen's College, Delhi
-Loyola College, Chennai
-Department of Science, Bangalore
-Miranda House, Delhi
-Hansraj College, Delhi
-Fergusson College, Pune
-Madras Christian College (MCC), Chennai
-Hindu College, Delhi
-Sri Venkateswara College, Delhi
As per my knowledge, bsc in economics is open for pcb students in most colleges. I would still advice you to go through individual college website to check their eligibility creteria. Most colleges even conduct entrance test for admission in this course.