what was the Nine Year's war?

Very little is revealed of The Nine Years' War, but it can be inferred that the conflict broke out in Europe, affected most of the planet, and caused massive physical damage. It is repeatedly stated that chemical and biological weapons were heavily used during the war, particularly in mass air-raids against cities. Following the war, which seems to have petered out rather than been ended by a decisive victory, the global economy collapsed and created an unprecedented worldwide economic crisis. To deal with the two catastrophes of the Nine Years' War and the Great Economic Collapse, the new world leaders tried to forcibly impose their new ideologies on Earth's populations. This met with widespread resistance, including large-scale riots at Golders Green and a massacre at the British Museum. Realising that they could not force people to adopt the new lifestyle, the World Controllers instead united the planet into the One World State and began a peaceful campaign of change. This campaign included the closing of museums, the suppression of almost all literature published before 2058, and the destruction of the few historical world monuments that had survived the Nine Years' War. By the time the novel is set, The World State is fully established and almost all citizens of Earth are under its full control.

i know it involved chemical and biological warfare.... and afterwards, the World States are formed...