Hello Amita ,

Yes , since you want to pursue BA History ,being from a science background ,you will have a reduction of 2.5% in you overall aggregate when you calculate your best of four. The best of four should include compulsory language either English or Hindi, one subject directly related to the course you are applying for, in your case history ,and two other elective or academic subject as per list A, in the absence of any of these you will have to deduct 2.5% .

Kindly visit the below link to know more about how to calculate your cutoff:

https://university.careers360.com/articles/delhi-university-admissions-how-calculate-best-of-four-marks

All the best