Delhi University (DU)

Central Institute of Education - University of Delhi is the best option. You can also go for these universities:
1. Jamia Milia Islamia
2. IGNOU (distance learning)

You are not eligible to take the lateral admission in B.Sc second year in Delhi University as there is no such provision in the university.

Admission process in DU colleges opens with notification in May end every year. Applications for admission are invited in June.

Both the universities are good for aerospace engineering. Their placements are good and almost same. SRM is slightly good as compared to UPES in aerospace engineering as they have their own integrated labs for this. UPES is also good and they also have infrastructure but their placement is less as compared to SRM.

As these are the private colleges they conduct their own exams. Through JEE you can take admission in government colleges

B.Sc (Hons) Maths in Delhi University colleges is based on best of 4 subjects in 10+2 board marks with inclusion of Maths marks. You may refer to DU website for 2016 cut off marks.

You may please refer to following link to have an idea about BA (Hons.) economics 2016 cut off in DU colleges: http://www.du.ac.in/du/uploads/Admissions/Cut-off/2016/First/290620161st_Cut_Off_DU_1.pdf