According to the reviews online, Ramjas College has the best Economics Department. It has well experienced and respected faculties who will put their complete focus on your learning and has contributed a tremendous amount of research work in the field of Economics.
Also it is the only economics department which holds a prestigious international economics conference called SAESM which provides students with a lot of exposure. Will definitely recommend you to take admission at Ramjas. You won't regret it.
Ramjas ranks above KMC. As far as the environment is concerned, whichever college you get admission in, you will get the similar feel, being in the North Campus.