Category refers to rank!
1-20k category 1 fees-usual
20-50K category 2 fees-high(Around 50k-1lac extra fees per year)
50-75K category 3 fees-higher(Around 1.5lac extra fees per year)
75-99.9K category 4 fees-highest(Around 2.5lac extra fees per year)
**Extra fees is depending on the branch you are opting for**