Sure, we knew that China has air pollution problems, but this photo getting attention on Reddit drives the point home. Reddit user hayzen77 posted a side-by-side comparison of his view across the wing of a plane he flew on from Australia (left) and to China (right). Though unknown factors like time of day could explain some of the difference (the photo originated on only-sometimes reliable Reddit), damn, do China's skies look polluted.

Inevitably, Reddit's community are ready to make wisecracks: "The cool thing about places like Shanghai is that you don't need that sepia effect," one thread commenter writes.