The Indian rupee is not a free float currency. That means that the reserve bank of India tries to make sure it doesn't fluctuate too much in value. While India is trying to move the currency towards free float, it isn't done yet. Basically, if anyone tries to speculate large amounts in rupees, the reserve bank will try to prevent fluctuations by speculating as well, or placing some sort of controls. This happened last year when the rupee started crashing and lost about 20%.

http://en.wikipedia.org/wiki/List_of_countries_with_floating...

In that respect BTC is similar to the USD/Euro/etc.

Also, Indian citizens are pretty heavily restricted from selling large amounts of rupees for dollars, etc. You need a lot of permissions and clearances for large amounts. (>$1M equivalent, earlier the limit used to be $1000!!)