I got obc 1684rank which branch should i choose & what about bs economics at iit kanpur

In the meanwhile you can also check for some Private Universities. There are some Private Universities which are equally good. They provide good Infrastructure, Faculty and Placements.You should choose a college which give you opportunity to work in live projects and give you good exposure. You may browse some web sites and check their details like Lovely Professional University, Nirma University, Noida International University etc...