Chairman Mao Zedong launched the campaign to reconstruct the country from an agrarian economy into a communist society through the formation of people's communes. Mao decreed increased efforts to multiply grain yields and bring industry to the countryside. Local officials were fearful of Anti-Rightist Campaigns and competed to fulfill or over-fulfill quotas based on Mao's exaggerated claims, collecting "surpluses" that in fact did not exist and leaving farmers to starve. Higher officials did not dare to report the economic disaster caused by these policies, and national officials, blaming bad weather for the decline in food output, took little or no action. The Great Leap resulted in tens of millions of deaths, with estimates ranging between 15 and 55 million deaths, making the Great Chinese Famine the largest famine in human history.
The Four Pests campaign (Chinese: 除四害; pinyin: Chú Sì Hài), 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 (Chinese: 打麻雀运动; pinyin: Dǎ Máquè Yùndòng) or eliminate sparrows campaign (Chinese: 消灭麻雀运动; pinyin: Xiāomiè Máquè Yùndòng), 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.