Q. When I am trying to delete a subscription to an SNS topic (specifically an email address) that is unconfirmed or pending , but from the AWS console the delete option is not visible.
Ans.
According to SNS architecture and design:
If subscription is APPROVED so no matter whether there is topic associated to it or not. User will be able to delete the subscription.)
If subscription is PENDING so no matter whether there is topic associated to it or not. Amazon will delete automatically the subscription after 3 days of creation.