CBSE 12th

Hello Saurabh,
You have asked an existential question. Answer unfortunately is straight forward no. Other institutions which take score from JEE Mains do accept lower scores, but these too have already been announced. You definitely need to score 75% or more in your boards to get into IITs.

You may opt for BBA, BMS or BBE degrees. In majority of universities admission in these degrees is based on entrance examination.

Hi,
It's very admirable that you are interested about pursuing economics but sadly without mathematics it's not possible to get a Bachelor's degree in economics as maths is an integral part of the mentioned subject.
Don't lose hope, there are some awesome subjects you can pursue after 12th.

Definitely, if you score really well in CAT examination, you will get a call from DMS, IIT-Delhi for sure.

BBA is the best option for management degree after 12th. You are advised to do BBA from Delhi University affiliated colleges.
IIM Indore offers 5-years Integrated programme in management (IPM). IPM is one of India's best 5-years management degrees.

Marks in boards doesn't aren't going to affect your rank from this year. And, if you've got 196, your rank is under 13k you will get any good NITs.

Hello Ayushman,
Firstly, start thinking that you can do it. Nothing in this world is impossible. Tips for preparing are:
Study all subjects every day.
Assign time for exercise, pranayama and entertainment.
Take the mock test every week.
Address weak areas emerging out of mock test results analysis. Once you do this, success will be yours.
Best wishes.

You can pursue professional courses like:-
Chartered Accountancy
Company Secretaries
Accounting Technician Course
Or you can choose Academic Studies like:-
M.Com
MBA
Also you can start preparing for Govt. Competitive Exams
All the best