Benchmark indices ended the session on March 21 deep in the red amid volatility. Sensex fell 571.44 points or 0.99% at 57292.49, and the Nifty was down 69.40 points or 0.98% at 17117.60. About 1516 shares have advanced, 1919 shares declined, and 140 shares are unchanged. Among the sectors, auto, banks, realty and power shed over a percent each while buying was seeing in metal names. The midcap index shed half a percent while the smallcap index added over 0.5 percent.