When the smog is severe, schools will suspend classes.
Tips
memory
霾 stacks 雨 (rain) over 貍 — a phonetic component also found in 狸 (racoon-dog). The rain radical marks it as atmospheric weather; modern Chinese binds it with 雾 (fog) into 雾霾 (smog), the ubiquitous word for China's pollution haze.
culture
Though 霾 is an ancient character found in 《诗经》 (Classic of Poetry), it was obscure until the early 2010s when 雾霾 crises forced it into daily weather forecasts, news tickers, and everyone's vocabulary.
Top rain radical — droplets falling from a cloud-shaped overhang. Indexes weather and atmospheric phenomena: 雪 snow, 雷 thunder, 霜 frost, 雾 fog. Haze, like fog, is reckoned as a sky-event under this radical even though it is dust suspended in air rather than water.
Bottom 貍 — the raccoon-dog or wild cat, an alternate form of 狸. Supplies the sound lí → mái through an older reading shift. The character contributes no semantic flavour; it is a pure phonetic frame inherited from when classical Chinese needed a rare graph to write the rare weather term for dust-laden air.
