According to the 2nd rule and guidelines of IGNOU:
Students who do not register for all semesters/years of a program, and fail to pay the fees within the maximum duration of the course, are eligible for re-admission.
For this, they will have to pay fees for the missed semester/years as per the rate applicable for the session for which they seek re-admission. In addition, they are also required to pay a pro-rata course fee for re-admission as per the rate given in Table-A for each of the course(s) that they have missed.
For further information consult your regional centre for the same.