Interest on saving 80tta provides a deduction is eligible only if have income ??

Sec. 80TTA deduction is available only against savings account interest offered to assessment u/h. IFOS in ITR. (max. 10000/-)

If not declared, plain deduction not allowed.

sir it has declared but they disallowed so asking you 

have you shown interest income in other sources?

Not allowed, As you declared interest under head income from other sources and there is a loss under head PGBP So, after inter head adjustment Gross total income will be Negative ( i.e loss which left after inter head adjustment will be c/f to next year)

So, if Gross total is negative than any Deduction is not allowed.

it's happen because first we have to do inter head adjustment and then after if any Income remain than deduction is allowed from that income.