Hello Abhigyan,
Pursuing MBA after B.Tech doesn't take away your knowledge in the subject. Infact pursuing a masters degree in management after B.Tech will actually increase the chances of your getting recruited. Especially since you are aiming for IIM it would be ideal that you prepare for CAT and look into the syllabus as well as percentile of cut off. Since IIMs are the number 1in management study institutes this will be nothing but a power up to your resume. Hope this helps and Good luck!
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