Architecture

Admission is through Tamil Nadu Engineering Admissions TNEA counselling based on the score obtained in NATA. Minimum eligibility to apply is that candidate should have cleared class 12th exams with Mandatory Subject : Mathematics. Other eligibility criteria:
Candidates having 10+3 Diploma (any stream

I guess, AAT is only for pursuing architecture from the IIT's
For NITs, only your JEE marks are enough.
Is this the Architecture Aptitude Test you are talking about?

You can either get directly admission in some private colleges or you can go for entrance exam for the top colleges. Do appear in entrance exam CAT to get admission into IIMs.

Yes, you can get a seat in RIZVI College of Architecture.This score is enough for a seat in the same campus.

This rank is enough for your admission in government colleges. You are eligible for getting a merit seat in government engineering colleges.

Yes, they are but with maths as a compulsory subject in their high school curriculum.