The domestic stock markets plunged, today, amid Asian market weakness, and the rupee depreciated for the second straight day against the dollar. The Sensex at the Bombay Stock Exchange slumped 301 points, or 1.2 percent, to close at 25,490. The Nifty at the National Stock Exchange fell 86 points, to 7,815. Other key Asian markets in Japan, China, Hong Kong, South Korea and Singapore lost between 0.5 percent and 1.4 percent. At the forex market, the rupee weakened 15 paise, to 66.77 against the dollar. And Brent crude oil futures fell 45 cents, to 47.63 dollars a barrel, on the back of a stronger dollar.