paragraph: In 2415 , after a virus in 2011 wiped out 99 % of the Earth's population , all of the survivors inhabit Bregna , a walled city-state , Which is ruled by a congress of scientists .  Although Bregna is idyllic , people are routinely disappearing and everyone is suffering from bad dreams .  on Flux is a member of the ` Monicans ' , an underground rebel organization who communicate through telepathy-enabling technology and are led by The Handler .  After a mission to destroy a surveillance station , on comes home to find her sister Una has been killed for being mistaken for a Monican .  When on is sent on a mission to kill the government's leader , Trevor Goodchild , she discovers that both she and the Monicans are being manipulated by council members in a secret coup .  This discovery causes on to question the origins of everyone in Bregna ; and in particular , her own personal connection to Trevor .  It turns out that everyone in Bregna is actually a clone , grown from recycled DNA .  With the dead constantly being reborn into new individuals and still bearing partial memories of their previous lives , there has been an increase in the troubling dreams .  Recycling and cloning became necessary since the original viral antidote made humans infertile .  Trevor's ongoing experiments , as with all his clone ancestors , has been trying to reverse the infertility .  on learns that she is a clone of the original Trevor's wife , Katherine and is the first Katherine clone in over 400 years .  One of Trevor's experiments , Una , was successful as she became pregnant . 
question: What is the name of the walled city-state where all human survivors resided and what problems did the inhabitants face in the city?
answer: Bregna- people are routinely disappearing and everyone is suffering from bad dreams