interest on income tax refund

vinay B S (Student CA IPC / IPCC) (43 Points)

01 August 2018  
on what basis, from which date interest on IT refund is calculated by department.

our it refund since 1999-2000 and many years was pending due to some issues. the issues were solved in court solved after that IT department given the refund with refund.

from 1999 to 2018 almost 20 years laps now we received with interest. the interest amount is look like very less.

hence I request you to help me in this issue & guide me how to calculate interest and how to get that amount from department..