The Sensex today fell by nearly 98 points in the opening trade, as funds and retail investors indulged in reducing their positions at prevailing prices amid weak Asian markets.The 30-share index, which had lost 186 points in the previous session, shed 98 points to 19,886 points. Metal, realty, banking and oil and gas stocks came under selling pressure and dragged the Sensex down. The wide-based National Stock Exchange index Nifty dipped below crucial 6,000 points level to trade 35.75 points down at 5,992 points.