This is the year 2051. The large population centers from the previous century were completely wiped out leaving radioactive areas devoid of life. The nuclear winter that followed the nuclear war changed the climate considerably and destroyed crop production for almost a decade following the war. Biopathogens were released in many parts of the world rendering these areas uninhabitable. All the vertebrates in Australia including humans died off due to biopathogens.
Insects are the highest life forms left in some parts of the world.
Humans are durable by nature and have survived in certain isolated, sheltered enclaves. These enclaves are very overcrowded. They are filled with many people squeezed into small geographic areas and have little food available. Conditions are harsh. The health care system consists of only a few hospitals in each enclave to take care of numerous people.