Hello Darsi,

Normalization occurs in every set taking into account every question paper set.

I assume that you are talking about the normalization procedure in GATE exam. Generally, normalization is done in those exams which take place in many shifts. It is done keepping in mind that the difficulty level of each question paper set is not the same and there are differences. So, if a candidate has some score in the tougher set and another candidate has the same score in the easier set, then the candidate of the tougher set will have a better score and rank.

Https://engineering.careers360.com/articles/gate-normalisation-process-how-scores-are-calculated