清 emphasizes 'light, fresh, clear' (the opposite of heavy or muddy), so
清香 is the kind of scent you'd associate with green tea, lotus, jasmine, freshly cut grass — never the heavy-sweet bouquet of perfume or spices, for which
浓郁 (nóngyù, 'rich') is paired with
香气 (xiāngqì, 'aroma').
清香 is also the technical name for one of the four main aroma classes of Chinese
白酒 ('clear-aroma' baijiu, exemplified by
汾酒 Fenjiu).
