The Sensex at the Bombay Stock Exchange declined 28 points, or 0.2 per cent, to 17,251 in early trade, today, on profit-booking by investors, amid weak regional markets. Later, the Sensex lost some more ground, and stood 75 points, or 0.4 percent in negative territory, at 17,204 in afternoon deals, a short while ago. The Sensex had gained over 175 points in the previous three trading sessions.Other key Asian stock markets in Japan, China, Hong Kong, South Korea and Singapore were down by between 0.1 percent and 1.4 percent, today, after weak economic data from the US.