Loreto College Kolkata and Bethune College are under Calcutta University. Their overall course structure will be similar. 

As one of my friends graduated from Bethune, I can say that their Economics department is much better than Loreto College.

The faculty is really great. They are highly experienced and extremely cooperative. They make sure that the students learn each and every topic from scratch. Even if you did not have an economics background before college, the professors teach you in a way that makes you familiar with the basics of the subject, hence gradually you get the full concept of it.

Due to this, it is suggested that you go for Bethune College rather than Loreto College to pursue an Economics Honours.