Here's why: if you don't hyphenate those adjectives, then all of the adjectives are modifying the noun. So if you didn't hyphenate above, then you would have awkwardness that reaches “near heights”and“Himalayan heights.” That doesn't really make sense. The hyphen tells the reader that...
Underlying most literally meanssituated underneath—lying under something, as in We have to fix the underlying layer before repairing the surface. Underlying perhaps most commonly means fundamental or basic. This sense of the word is used to describe things that are the basis, foundation, or cause...