Hi Vamshi! As far as the top 20 B-schools are concerned, the admission takes place on the basis of GD/WAT and PI. the selection procedure or the rounds may vary from institute to institute. For example, some B-School may, whereas some may conduct WAT. On the other hand, some may conduct Psychometric Tests or Case Study or Group Exercise in lieu of GD. The format may vary, but no top B-School accept students only on the basis of CAT scores.