Category 1 is for those who got ranks between 1 - 20k. They pay around 1.5 lakh per year as fees. It is the general merit list.

Category  2 is for 20k to 40k rank.

They need to pay 2 x (fees of cat 1 )

Lakh per year as fees and it goes on till cat 4. What is worse is that the seats which have gotten over during the phase 1 (rank 1 to 20k ) surprisingly becomes available for the subsequent phases for some extra money.

Category 2/3/4 is similar to management quota.  Vit will never disclose whether you are from category 1 or 2 or 3 or 4 and no one will get to know what your rank was in viteee until and unless you disclose it to someone.