江河日下

jiānghérìxià
  1. rivers pour away by the day (idiom); going from bad to worse
  2. deteriorating day by day

CEDICT

to worsen by the day; to get worse with each passing day

Wiktionary

江河之水，源于雪山，春夏冰雪溶则水盛，秋冬冰雪渐凝，江河水则渐少。比喻情况日渐衰微，一天不如一天。

重編國語辭典

情况一天比一天糟糕

維基詞典

Entry Composition

1 江河 jiānghé river
2 日下 rìxià
  1. (literary) to go down day by day
  2. at the moment; currently
  3. to go down day by day