primary defeceit is the root caused of fiscal defeceit . explain

Primary deficit refers to difference between fiscal deficit of the current year and interest payments on the previous borrowings. Algebraically, 

Primary Deficit = Fiscal Deficit – Interest Payments

The total borrowing requirement of the government includes the interest commitments on accumulated debts. Primary deficit reflects the extent to which such interest commitments have compelled the government to borrow in the current period. It indicates, how much of the government borrowings are going to meet expenses other than the interest payments. The difference between fiscal deficit and primary deficit shows the amount of interest payments on the borrowings made in past. So, a low or zero primary deficit indicates that interest commitments (on earlier loans) have forced the government to borrow. For instance, in India, interest payments have considerably increased in the recent years. High interest payments on past borrowings have greatly increased the fiscal deficit. To reduce the fiscal deficit, interest payments should be reduced through repayment of loans as early as possible. This is why, primary deficit is regarded as the root cause of fiscal deficit.