I wouldnt say you will never be able to secure a seat in IIM, but honestly speaking, it would be tough, irrespective of your Category. However, you may still have fair chances in securing Interview Calls from some of the IIMs especially newer IIMs (CAP), with a strong performance in Class 12, Good Grades in Graduation and an Excellent 99+ Percentile CAT Score. Secondly, apart from IIMs and CAT, there are many Other Top Management Entrance Exams like MAT, XAT, SNAP, NMAT, IIFT and many others which too are entrance gateways to some of the Good Business Schools in India. Considering the rising demand of Managers, you must target not only the IIMs but parallely the Top 50 NIRF Management Institutes. Secondly even in future after a strong work experience, you may opt for a Executive Program in Management from some of the IIMs.

For more information about IIM Admission Criteria do follow the link below https://bschool.careers360.com/articles/iim-admission-criteria/amp