Continuing its weakness for the fourth day on Wednesday, theIndian rupee tumbled by 29 paise against the dollar to breachthe 40-mark for the first time in five months with the shortageof U.S. currency getting accentuated by the global crude priceswhich hit fresh records. In brisk activity at the inter-bankforeign exchange market, the domestic currency touched a low of40.24 before closing at 40.19/