You will be given a definition of a task first, then some input of the task.
Generate a question which can yield the answer mentioned in the input. Generated question must be answered by the answer provided in input, without using any extra knowledge.

Context : The 1991 Uttarkashi earthquake occurred on 20 October 1991 in the Uttarkashi and Gharwal regions of the Indian state of Uttarakhand.
Answer : 20 October 1991
Output:
When did 1991 Uttarkashi earthquake occurr?