China’s Four Pests campaign is a great example. As the campaign says, China had a bit of a pest problem. One of these particular pests was the sparrow. The government decided it would be a great idea to launch an “exterminate sparrows” campaign. The only problem was sparrows ate other pests such as bedbugs and locusts.
In short, they sucessfully curbed the “sparrow problem” and replaced it with a “locusts and bedbugs problem”. This ultimately upset the ecological balance and further lowered the rice yields. It was a complete disaster