CBSE

Hi Ashwin!
You will have to appear for Xavier's entrance exam called XIC OET. You can find the details about the exam here https://www.shiksha.com/college/xavier-institute-of-communications/exams/xic-oet.

Hi Arijit,
In no particular order, here some of the best ones:
Don Bosco Senior Secondary School
Sarla Birla Gyan Jyoti
Delhi Public School
Gurukul Grammar Senior Secondary School
Miles Bronson Residential School
Army Public School
Faculty Higher Secondary School
among others.

Yes, Madina Public School is affiliated to CBSE.

Admission is based on marks obtained in 10+2. Interested candidates can apply online with the required information.
Eligibility:
Candidate must have passed 10+2 from recognized board. Regards.

You can refer to Arihant experts, GKP, Suresh Bhavnagar, Nidhi Taneja as these are the best material available today, refer to any one of them and go through it completely.

You have not mentioned your stream which you opted for in 12th class, so it is difficult to suggest you something but to become an IAS officer, you need to be a graduate or studying in the last semester of graduation course, the stream doesn't matter if you have a degree, you are eligible. Most subjects included in UPSC are of humanities stream so you need to be good in that particular portion and there will be a paper which is concerned to your subject that you have studied in your graduation so you need to put quite a hard work.
All the best.

Hello,
You said 430 marks. This means, 86% and this is really enough. So, don't worry if you are confirmed that you are getting marks nearby and you can get admission easily. But try to score more marks in JEE mains as Sastra University gives more preference to JEE mains marks.

Where do you wish to apply?

That is not an "important exam", it's "improvement exam". You can go for the improvement exam in this case.
All the best.

MBBS, pharmacy, biotechnology, D.Pharma, etc.