Refund granted by ITAT

During assessment AO ordered for Demand of 1,00,000.
Assessee filed CIT Appeal and CIT ordered refund of 1,00,000.
AO filled ITAT appeal and ITAT ordered redund of 1,60,000.

Now the question is that on what amount and what period interest on this refund will be given by income tax department..
please provide section detail too