Civil Servant (IAS/PCS)

CBI recruits candidates through direct recruitment, deputation, promotion by seniority or through Limited Departmental Competitive Examination. All direct recruitment of Group C posts for sub-inspectors, constables and lower division clerk are made through Staff Selection Commission (SSC). Procedure to join in CBI as sub inspector:
Sub inspectors are recruited through SSC's Combined Graduate Level Examination (CGLE), followed by medical examination and personal interview. To join IB, you have to apply for the Combined Graduate Preliminary examination (CGPE). It's nothing but CGLE only. This exam is conducted by the SSC every year. The eligibility required for this examination is given below (at last in the answer). Education qualification:
To apply for this examination, a candidate should be a graduate in any discipline from a recognized university. Those appear in the final year examination are also eligible. Age limit:
For the Intelligence Bureau (IB), candidate's age should be between 20 to 27 years. There is relaxation in age for the reserved category candidates like scheduled castes/ scheduled tribes, etc.

CBI recruits candidates through direct recruitment, deputation, promotion by seniority or through Limited Departmental Competitive Examination. All direct recruitment of Group C posts for sub-inspectors, constables and lower division clerk are made through Staff Selection Commission (SSC). Procedure to join in CBI as sub inspector:
Sub inspectors are recruited through SSC's Combined Graduate Level Examination (CGLE), followed by medical examination and personal interview. To join IB, you have to apply for the Combined Graduate Preliminary examination (CGPE). It's nothing but CGLE only. This exam is conducted by the SSC every year. The eligibility required for this examination is given below (at last in the answer). Education qualification:
To apply for this examination, a candidate should be a graduate in any discipline from a recognized university. Those appear in the final year examination are also eligible. Age limit:
For the Intelligence Bureau (IB), candidate's age should be between 20 to 27 years. There is relaxation in age for the reserved category candidates like scheduled castes/ scheduled tribes, etc.

Hi,
CBI recruit candidates through direct recruitment, deputation, promotion by seniority or through Limited Departmental Competitive Examination. All direct recruitment of Group C posts for sub-inspectors, constables and lower division clerk are made through Staff Selection Commission (SSC). Procedure to join in CBI as sub inspector:
Sub inspectors are recruited through SSC's Combined Graduate Level Examination (CGLE), followed by medical examination and personal interview. To join IB, you have to apply for the Combined Graduate Preliminary examination (CGPE). It's nothing but CGLE only. This exam is conducted by the SSC every year. The eligibility required for this examination is given below (at last in the answer). Education qualification:
To apply for this examination, a candidate should be graduate in any discipline from a recognized university. Those appear in the final year examination are also eligible. Age limit:
For the Intelligence Bureau (IB), candidate's age should be between 20 to 27 years. There is relaxation in age for the reserved category candidates like scheduled castes/ scheduled tribes, etc.

Since, you belong to Science stream but preferring Civil Services. So, I would recommend you to go for BA Hons History from any reputed university across India, since I am also a History graduate from University of Delhi, but not aspiring for Civil Services. Taking History will be very helpful, though you can take political Science as well. Other than this, It came to my mind, that a possible question can arise to you that being a Science student, Going arts will be inconvenient, I am sure it will be, but the fact is, For IAS, History is must, because if you won't take it in your main subject, the general studies aspect has History and General studies paper is must, So you have no option but to read History.