汚染
おせん · osen · JLPT N3 · noun
pollution
🏭 汚染 = dirty + dye: grime that soaks in and stains everything
汚 (o) means dirty or stained, as in 汚い (kitanai, dirty). 染 (sen) means to dye or soak in, as in 染める (someru, to dye). Pollution is dirt that seeps into water, air or soil like dye. Hook: oh, sen-sitive river, now stained.
染 — water 氵 + nine 九 + wood 木
染 depicts the dyeing process: 氵 (water) for the dye liquid, 木 (wood) for plant-based dyestuffs, and 九 (nine) suggesting repeated dippings to deepen the color. Originally meaning 'to dye cloth,' it later extended to figurative senses like 'to be influenced' or 'to contract' (as in illness).