New Delhi, Aug. 3 -- Monday's trading session took an unusual turn in the Indian stock market, as the Nifty 50 and the Sensex ended with a sharp divergence, leaving many participants on Dalal Street puzzled.

Both benchmark indices had largely moved in tandem throughout the session, but in the final two minutes of trade, the Nifty 50 surged nearly 201 points to settle at 24,773, up 1.60% from Friday's close.

The Sensex, meanwhile, ended with a comparatively modest gain of 0.70% at 78,639. The unusual divergence was triggered by the implementation of the Closing Auction Session (CAS) in the equity cash segment, which became operational on Monday.

The new auction-based mechanism, introduced by the Securities and Exchange Board of India (S...