三年困难时期
The Four Pests campaign (), was one of the first actions taken in the Great Leap Forward in China from 1958 to 1962. The four pests to be eliminated were rats, flies, mosquitoes, and sparrows. The extermination of sparrows is also known as smash sparrows campaign () or eliminate sparrows campaign (), which resulted in severe ecological imbalance, being one of the causes of the Great Chinese Famine. In 1960, Mao Zedong ended the campaign against sparrows and redirected the fourth focus to bed bugs.