At the interbank foreign exchange market, the rupee slumped 39 paise, to slip below the 60-mark, and close at a six-week low of 60.16 against the dollar, on Monday. The rupee fell on sustained dollar demand from oil importers, as oil prices climbed to near nine-month highs. Weakness in the domestic stock markets, amid a rise in wholesale price inflation also weighed on the rupee.