The doldrums

[Justin Bieber]

a.k.a Intertropical [Convergence] Zone (ICZ)
Early sailors named this belt of calm the doldrums because of the low spirits they found themselves in after days of no wind. To find oneself becalmed in this region could mean death in the era when wind was the only [motive] force available, and it was certainly a depressing experience to be isolated, in the middle of the ocean, in a hot, [muggy] climate.