Do I have to give CAT first and then only I'll be able to apply for IRMA or there are some other ways and What is IRMA's accepted score?

Yes you have to give CAT first. then irma has its own test named as issues of social concern test. the combined score of CAT and this test ensures your admission into irma. the CAT cutoff is around 75 percentile for general category.

Kiran Dhole is correct except for the Cutoff part. Irma prepares cutoffs for G.D.-Interview rounds based on aggregate marks;not percentile. For general category it's preferable that one scores above 90 percentile and good aggregate score.Because IRMA gives Considerable weightage to CAT Score and the