One of my friends studied in Lady Brabourne College with Physics (Hons). The criteria was an exact 100 in physics. The criteria for other boards may be equal or vary.

This might have changed over the years, but chances are very less if you have scored less than 95.

St Xavier’s College’ Chemistry (Hons.) criteria is around 95–98%. Some students with 90% or above will get admission through 3rd or 4th list if there are vacant seats.

Therefore to secure a seat, your overall percentage must be more than 95 and in the subject you want to pursue for your honors, you must have a higher score than 97, from whichever board you graduate from.