Dear Rizwan, we are not sure how bad is 'bad'. But there is a rating scale that most IIMs follow. It might not be exactly the same across all IIMs but this is just to give you a faint idea of the rating system.

10th Rating:

Percent score       Rating Score

<= 55                              1

> 55 and <= 60               2

> 60 and <= 70               3

> 70 and <= 80               5

> 80 and <= 90               8

> 90                             10


The same rating score is used for 12th Science /Commerce Streams. For Arts/Humanities:

Percent score        Rating Score

<= 45                                1
> 45 and <= 50                 2
> 50 and <= 60                 3
> 60 and <= 70                 5
> 70 and <= 85                 8
> 85                                 10

From each Academic sectors top 5% from each stream and each Category will be short listed. It might look like:


Category                             Upper Limit

General                                      100

NC-OBC-cum-transgender         57

SC                                                32

ST                                                16

PwD                                              6

Now if this is how candidates are selected, even if you.lose out on Academic marks, you can still make it to the shortlist, if you can really manage to do well in CAT. So irrespective of your Category, your target should be 95 percentile atleast.