Daily Chinese Idiom Guessing Game
Describes a place so crowded that there is no space even for water to flow through.
汇排泄。象是连水也流不出去。形容拥挤或包围的非常严密。
宋·释道原《景德传灯录》德山门下，水泄不通。”
The subway station was packed so tight that people were squeezed together like sardines.