Treatment of Unamortized Preliminary Expenses as per Income Tax Act

As per Section 35D of Income Tax Act, the assessee shall, be allowed a deduction of an amount equal to one-fifth of expenditure incurred before the commencement of the business for each of the five successive previous years beginning with the previous year in which the business commences.

My question is if we forget to claim deduction in ITR in earlier 5 years can we claim the same in 6th year (in case of Private Company)?