Hello Promod,

Most of the college have seat process as they have to prior notice to AICTE for increasing seat.

Almost all private institutions have seat process, maybe some institutions provide unlimited seat but their authenticity will not be good.

Private institutions have definite number of seats in each department to regulate the batch with efficiency.

You can know about seat process of each college on their official website.

If you have any questions remain than comment below 

Regards...