Writing in Mint, Mobis Philipose points out that Nifty options trading appears to have crossed a decisive turning point, and looks at some of the factors at work. Click on the chart above (from his article) to see it more clearly. From Jan 2008 to September 2008, Nifty options activity went up from below 200k contracts/day to roughly a million contracts a day, even overtaking the extremely active Nifty futures. I feel this is only the beginning, for the full impact of SEBI's DMA announcement hasn't yet played out.
The brainpower and systems that are doing this on Nifty will readily do this for the currency, once the ban against exchange-traded currency options is lifted.
You might like to see NSE's monthly publication with facts about derivatives trading.