Hi Raunak sir,
Everyone thought Nifty index would correct 20% just like so many major stocks did. Add to it the Korean war prospects, European Soverign Debt default scenario, LIG Scam, 2G spectrum scam,
Analysts on TV, great run up in Nifty from 5400 levels, hedge funds and mutual funds in North America and Europe being closed for Christmas holidays, nifty being in the downtrend channel... so many things happened.
5400 seemed like a strong support. So, many people bet on the negative side...