Earth has become uninhabitable by humans,the cause was so much pollution and such,the oxygen on earth became more and more polluted over time,the more rich people turned into robots,although about 1% of Earths population was basically immune to the pollution,they have been called survivors and are seen as spoiled and are disliked by many,,so many humans have been turned into robots to survive,other humans died due to not being able to afford or construct these new body's,and gas mask only worked for so long