Science

Your question gives me the impression that you have absolutely no basic knowledge of how Disaster Management works. The National Disaster Management Authority (NDMA) is the main government body responsible for planning and capacity building to be prepared for an emergency disaster situation. The National Disaster Relief Force (NDRF) is the most important organisation that that deploys personnel for search and rescue operation in the event of a disaster. The National Institute of Disaster Management (NIDM) provides the training for disaster management. All three are part of the Ministry of Home Affairs. The Ministry of Science and Technology has a department of scientists in the field of Geology and Earth Sciences who offer advice NDMA, NDRF and NIDM. The Indian Police Service and the Defence Forces have their own training programmes (for selected personnel) in disaster management and offer their services in the event of a disaster. Apart from what I mentioned above, Aniruddha Academy of Disaster Management (AADM) in Mumbai is a not-profit organisation that provides training and volunteers in the event of an emergency. AADM is suited for teenagers, as the first step, who wants to work in Disaster Management. Finally, the Indian Institute of Remote Sensing (IIRS - part of ISRO) based in Dehradun offers Postgraduate and PhD courses in Geoinformatics, Geosciences, Forestry and Ecology, Marine and Atmospheric sciences. Postgraduates and Doctorates from IIRS work are employed by NDMA and ISRO. My point is that, instead of studying M.Sc in Disaster Management in TISS, I would recommend you to study M.Sc in Geoinformatics or Geosciences at IIRS.if you are eligible. That is the best option. If you are not eligible for these courses, then you can study MA Natural Resources and Governance or MA Rural Development at TISS. These courses will prepare you for 'redevelopment after disaster'. Anyways, you look at it, you should be aiming for a central government job in the field you have chosen or an NGO.

MIT Arts, Commerce and Science College and Alliance School of Business are equally good. Some of the important points while selecting an institute - Accreditation of the institute, institute's infrastructure, teaching faculty, specialization offered, past placements records., tuition fees, city preference and industry interface. As both the institutes are having the campus in Bangalore and Pune. Industry exposure is good for students in either of the college. If possible a visit to college is better option to get a reality check. Also, get in touch with college alumni's through the social network to get information about the latest changes if any.
You can compare the course fee, placements, students review, facilities offered and seats-
https://www.shiksha.com/resources/college-comparison-170945-147327

Maths is the basis subject and involved in almost all subject in little bit because math is a subject which helps to solve problem easily.
ACCA is equivalent to Indian CA except the geographic recognition it has. You will study accounting, taxation and finance subjects as practical papers which require basic mathematics. Association of Chartered Certified Accountants (ACCA) is a course in which candidate has to learn the basics of maths skills which is enough to earn this degree. But difficulty is related to the individual. I would say the content isn't that difficult, but there's a lot of content to get to grips with. The quality of your tuition and factors like study time also make a difference.
For more detail about the maths visit the link provided below:
http://www.accaglobal.com/in/en/qualifications/ready.html