Civil Servant (IAS/PCS)

NCERTs are the Geeta and Bible for freshers in context of UPSC prep.

They both are two different stages, prelims 1st and main 2nd. You have to clear them separately.

Yes, medical facilities are free to IAS. They get dearness allowance, traveling allowance and medical allowance with their payment.

You will get pension until your whole life and you can be appointed as a secretary of any ministry after retirement too.

The minimum age for UPSC exam is 21 so in 2021 you will be eligible.

Some of the best IAS coaching in Tamil Nadu are:
All India Civil Services Coaching Centre
Coaching Center Chennai, Tamil Nadu
Vetrii IAS Study Circle
Coaching Center Chennai, Tamil Nadu
Shankar IAS Academy
Coaching Center Chennai, Tamil Nadu.

AIR is the abbreviation for ALL INDIA RANK. This indicates the rank of a candidate in the exam in all India level.

In UPSC prelims, you need to cover: general studies - History, geography, polity, economics and Science. For CSAT paper 2, aptitude and general mathematics.

UPSC CSE PRELIMS SYLLABUS
Paper 1 - General Studies:
This includes areas like; Indian National Movement, Indian Polity, Basic Economic Understanding, Geography. While these are static part of the syllabus, the dynamic part includes current affairs, General Knowledge and that does not proper definition, thus making the syllabus quite vast. Paper II - Aptitude Test:
Paper II is dynamic in nature and includes mathematics, reasoning, analytical ability, and interpersonal skills. All these areas require spot mental ability.

Yes, you are eligible as UPSC CSE needs only graduation to appear in its exam and it doesn't matter what the field of graduation is.