The document provides a summary of derivative market activity in India for October 5, 2010. It notes that open interest in Nifty futures increased by 1.71% while open interest in Minifity futures decreased by 8.05%. Implied volatility of at-the-money options increased from 20% to 21% despite rising market levels. Specific stocks like NMDC, BHUSANSTL, and UCOBANK saw large increases in open interest, while stocks like ORCHIDCHEM, ZEEL, and SAIL saw decreases. The put-call ratio for various indexes and stocks is also provided.