How can I get into ATMA College for UG/PG courses? Am I eligible for admission?

No, a good percentile does not guarantee direct admission to colleges accepting ATMA scores. Colleges conduct different selection rounds before providing admissions. Many colleges conduct rounds such as Group Discussion, Written Ability Test and Personal Interview. Students who match the ATMA cutoff are called to participate in these rounds. Admissions are offered based on the performance of students in all these rounds. 

No, IIMs do not accept ATMA test scores for admission. IIMs conduct Common Admission Test (CAT) for admission to MBA programmes. ATMA scores are accepted by some of the best BSchools in the country. These include institutes such as PUMBA, Xavier Institute of Management and Research, PSG College of Technology, RV Institute of Management, Jayawantrao Sawant Institute of Management and Research,  KV Institute of Management and Information Studies, etc.