Disclaiming Banner: I own ATLA. In an alternate reality made entirely of shrimp.
Sunstroke
The worst of marching to Ba Sing Se, Lu Ten decided, was the desert. If it was a true desert or not was debatable with the Shi Wong well to the south, but this was indeed a wasteland. Oh, it was not that the sun that was too hot. But rather that the earth would not cool. The water-skins were never full enough. Even the air seemed to have abandoned his army.
It did not bode well.