whether the cause of this is happening, is it something to do with the decision of the south korea government?
The fall in the price of bitcoin is no way connected to the decision of the south Korea government, because if you know bitcoin very well you will understand how it work's by this time last year 2017 the price of bitcoin was not up to $2000 but in may June the same year it rises to $5000 to $6000 and before the end of the year 2017 bitcoin was high above $10000 to $20000. So this current happening in the price of bitcoin is part of bitcoin nature always volatile.