Not understanding sparrows role in the game caused by the Four Pests campaign. MILLIONS DEAD.
The ecological repercussions translated into a humanitarian crisis of unprecedented proportions. The absence of sparrows, which traditionally kept locust populations in check, allowed swarms to ravage fields of grain and rice. The resulting agricultural failures, compounded by misguided policies of the Great Leap Forward, triggered a severe famine from 1958 to 1962. The death toll from starvation during this period reached 20 to 30 million people.
https://en.wikipedia.org/wiki/Four_Pests_campaign#Consequences
Is what I said, "let's abandon" is what you said.