You know there are many factors that could affect the price of bitcoin like banning the country and losing bitcoin account password. But the must factor the could affect bitcoin price is to the holders who getting panic and they sell it even they loss. That is only my opinion.
Panic selling is the effect of any reason of price fall down, that news of banning or whatsoever is just the front that make a good or bad news and if it is a bad news we can expect its intentionally made to make some panic in the market.