In choppy trade, the Bombay Stock Exchange benchmark Sensex today fell by nearly 70 points to extend losses for third straight session with investor sentiment remaining dampened. The 30-share Sensex closed at 16,283. The key index has lost over 450 points in the last two sessions. The wide-based National Stock Exchange index Nifty also fell by 20 points to 4,826.Traders said, market extended its losses on concerns that the government might halt stimulus spending as the central bank tightens monetary policy.