Sensex crashed 856.65 points to end at 74,454.41, while Nifty fell to 22,553.35 points on Monday, sending the indices to their lowest levels in eight months. "This downturn was largely influenced by ongoing [FII] selling...due to global market dynamics favouring...US and China," Research analyst Vaibhav Vidwani said. Notably, US' Wall Street marked its worst session in a year on Friday.