NSC interst taxable ?

NSC interest is taxable on accrual basis i.e annually and not on maturity..

I had not declare interest in last 4 years in income tax  how I can show in this year ? Can I show only this year interest as amount is invested automatically in nsc again. 

I had not declare interest in last 4 years in income tax  how I can show in this year ? Can I show only this year interest as amount is invested automatically in nsc again.

Check his AIS report and follow the income declared in it.