How do we adjust for depreciation in principal amount for a deposit in a foreign currency. E.g. if I deposit 100 INR as principal and I get 10INR as interest. However, the USD-INR exchange in the year of deposit was 70INR = 1USD and in the tax year it changed to 80INR=1USD. In other words, the principal itself reduced in value due to exchange rate change. How do we account for that?
