Many different worlds exist in a state of "parallel worlds," but not all of them; some have diverged into another form of development, such as the one with the bone dragons.
The world Zheng Yichen was in was quite similar to Hazy City, uh, lacking many of the distinctive features of that world, but generally similar with satellites, cars, trains, airplanes, and so on — all the usual things were present, and the entertainment information in the magazine he was holding also aligned with Zheng Yichen's understanding.
It's akin to the development level of the 21st century. From some incomplete newspapers and the like, he'd learned that the apocalypse of this world originated from a biochemical virus.
Typically, unless a biochemical virus spreads over a wide area simultaneously, it's unlikely to trigger an apocalypse, right? According to the newspapers, this apocalypse wasn't related to a virus leak, but to an aberrant and extraordinary downpour.