The Sensex at the Bombay Stock Exchange lost 128 points, to a one month closing low of 17,313, amid a weak rupee, and falling Asian markets on Wednesday.The Nifty at the National Stock Exchange fell 48 points, or 0.9 percent, to 5,226.Stock markets in Japan, China, Hong Kong, South Korea and Singapore lost between 0.3 percent and 1.7 percent.