(of places) extremely dirty and unpleasant, often because of lack of money

Many prisons, even today, are overcrowded and squalid places. 时至今日，许多监狱仍旧拥挤不堪，肮脏至极。

(of situations and activities) not moral; involving sex and drugs, etc. in an unpleasant way

It's the usual squalid rock star tale of drugs, sex, and overdoses. 那是常见的摇滚歌星堕落的故事——吸毒、纵欲、过量服用麻醉品。