India's Closing Auction System (CAS) debuted on Monday, triggering a sharp 200-point jump in Nifty during last five minutes of trading. Under CAS, closing prices are determined through a single-price auction, replacing the earlier method where F&O stock closing prices were based on the last 30 minutes' volume-weighted average price. Nifty settled at 24,774.30 points, up 1.6% from Friday's close.