That gang of human traffickers committed heinous crimes and sparked public outrage.
Tips
history
First found in Zhou Mi 周密's Song-dynasty miscellany 《齐东野语》: 今开庆误国之人，罪恶滔天 - written about the corrupt officials of Emperor Lizong's Kaiqing era who, in Zhou's view, mismanaged the empire so badly their crimes flooded up to the sky.
memory
Picture water 滔 surging until it reaches heaven 天 - that's the volume of 罪恶 (evil deeds) the idiom describes. Used today for war crimes, mass murders, and trafficking, never trivial offenses.
