Hiiii dear,
Eligibility criteria for B.Arch is:
Candidates who have passed 10+2 and have secured at least 50% marks in aggregate with Mathematics, English, Physics, and Chemistry will be considered eligible.

They should have passed the qualifying exam in the year 2016, 2017 or are appearing in 2018, will be considered eligible to first year of the B. Arch. course, subject to an aptitude test.
OR
Diploma holders (10+3) recognized by Central/State government are also considered eligible provided they have passed the Diploma with 50% marks in aggregate.
Good luck.