The Arduous March is the term that is used in North Korea to refer to the famine that lasted for most of the 1990s. It is very difficult for outsiders to know the details of the events because North Korea is an extraordinarily closed society. It does not want foreigners or its own people to have too much knowledge about what goes on for fear that it will be used against the regime.
Any closed society would surely try to keep the details of such a horrendous famine as secret as possible. The North Korean regime is more secretive than any other. For example, Kim Jong Il had been dead a few days before the regime announced his death. To that point, there was only one known photograph of Kim Jong Un. When you have a society that is that closed on things that do not make it look bad, imagine how closed it will be with regard to something like this famine that makes it look completely inept and helpless.