The Indian rupee dropped sharply by 90 paise to 66.90 rupees against the American currency in late morning trade on persistent dollar demand from banks and importers on the back of firm dollar in overseas amidst sudden fall in equity market.The rupee resumed lower at 66.29 rupees per dollar as against the last closing level of 66.00 rupees per dollar and dropped further to a low of 66.90 rupees per dollar.