NATA

Hi Arbaaz,
As far as I know, to get admission in B. Arch in IIT - Kharagpur you have to clear JEE advanced first and then clear the B. Arch paper conducted after the results are out and not through NATA. IIT Roorkee offers admission on the basis of Architecture Aptitude Test. Architecture Aptitude Test (AAT) 2015 is an architecture entrance exam for admission into IITs into the 5 years undergraduate B.Arch Course.
Eligibility for Architecture Aptitude Test: Only those candidates who would have given B. Arch program (available at IIT Kharagpur and IIT Roorkee) as one of their choices while filling their choices online will be eligible to write AAT. Moreover you have to clear JEE Advanced also. To Appear in JEE Advanced you should have cleared JEE Main paper 1.
List of top colleges accepting NATA score are :
http://goo.gl/U5X56X1
Hope this information helps. Please feel free to revert.
Wish you luck.

Hi Arbaaz,
The common merit list that is prepared is based on the candidate's performance in the exam. Please remember that only those aspirants, who have taken both Paper 1 and Paper 2 will be considered for ranking.
As far as the marking system is concerned, the marks secured by a candidate in Physics will be equal to the marks he/she secures in Physics part of Paper 1 plus marks in Physics part of Paper 2. The same procedure is followed for Chemistry and Mathematics too. Thus, the sum of the marks obtained in individual subjects in JEE Advanced 2015 will be the aggregate marks for the aspirant.
Coming back to the merit list, aspirants must have scored at least 10% in each subject and 35% in aggregate in order to be in the common merit list(CML). Separate lists will be prepared for the prepared for general, OBC (NCL), SC and ST category students.
Students from OBC (NCL) category should have scored at least 9% in each subject and 31.5% in aggregate in order to be in the OBC (NCL) merit list. However, students from the SC and ST categories must score at least 5% in each subject and 17.5% in aggregate in order to be in their respective merit lists.
Merit lists for PwD candidates:
Separate merit lists will be prepared for PwD candidates who further belong to the GE, OBC (NCL), SC and ST categories. To be in these merit lists, candidates must score at least 5% in each subject and 17.5% in aggregate.
For more details on CML, kindly refer the link below:
http://goo.gl/1nDRVy
Hope this information helps. Please feel free to revert.
Wish you luck.