There are actually two important contexts related to 1984, the real context in which George Orwell was writing and the fictional context of the society of Oceania.
The actual publication date of the novel was 1949, shortly after the Allies had defeated Hitler and the Axis powers in Europe. The Cold War between Stalinist Russia and the West was at its height, Franco controlled Spain, and it seemed to Orwell that democracy and liberal society were under threat from dictatorship and totalitarianism partly enabled by mass media and technology.
The fictional context of 1984 is a Britain which has succumbed to totalitarianism. The environment is in many ways drably functional, designed so that surveillance is ubiquitous. Every aspect of people's lives is controlled and monitored. Telescreens are an omnipresent technology used both the brainwash and observe people.