Hey Akshita 

For Bcom honours, Economic honours and maths honours having maths in 10+2 is compulsory other than that best of four is any three main subjects in which you have scored the highest amongst all five to six subjects that you have, English is compulsory to include in your best of four regardless of the marks scored be it highest or lowest. Same criteria is for Bcom programme except maths is not compulsory subject to be eligible. 

All this information is as per University of Delhi, Eligibilty criteria.