Yes, albeit, with certain limitations.  IBKR provides cash accounts the ability to trade products denominated in a currency other than the designated base currency of the account as long as the account is classified as a multi-currency cash account (i.e., maintains Forex trading permissions).  To trade a security denominated in a non-base currency, the account holder must either first deposit the appropriate currency into their account or perform a currency conversion via the IdealPro venue.  Regardless of the method selected, one needs to ensure that a sufficient balance of the appropriate currency exists in order to cover the purchase price of the applicable security including commissions prior to submitting the order or it will be rejected. This implies that IdealPro currency conversions must settle prior to the converted funds being available for a subsequent transaction (e.g., if you are converting USD into EUR for the purpose of purchasing a EUR denominated stock, you would not be able to enter the stock order until the conversion trade had settled two business days later).

Individuals trading futures in a cash account should note that futures variation is settled in cash and any variation which serves to generate a cash deficit in any given currency type (i.e. variation exceeds available cash margin) will result in a forced position liquidation in an amount sufficient to eliminate the cash deficit.

Finally, note that cash accounts are restricted from holding a short balance in any non-base currency as this would constitute a margin loan.  In addition, clients of IB India are not allowed to maintain a multi-currency cash account and may only maintain assets which are denominated in INR.