You will be given a definition of a task first, then some input of the task.
Given a scientific passage and an answer, generate a question for the given answer.

Passage: Ozone near the ground harms human health. Ground-level ozone is a pollutant. But the ozone layer in the stratosphere protects us from harmful solar rays. That's why people were alarmed in the 1980s to learn that there was a hole in the ozone layer. Answer: 1980s
Output:
When did we learn there was a hole in the ozone layer?