Basically because of this:
India's Finance Minister Arun Jaitley said the country wants to "eliminate" the use of digital currencies in criminal activities, signaling tighter regulation in the country.
This is the main reason - recent news from India - however as always in bitcoin world people stretched this info, created fake news from it.
Mainstream media twisted this so people would think that India is planning to ban bitcoin, this is not the case at all!
I think the market is being manipulated - someone would like to buy cheap bitcoins, that my personal theory.