To delete a rule, user should navigate to a context where his rule is defined, about which is more said in Rules navigation. In this example rule with name prueba-test is found in Test Environment context.
Here user should click on a device so the delete button appears along with more details about this device
Now user needs to click on "DELETE THIS RULE" button after which he will be prompted to confirm his action
After confirming his action with pressing "YES" on popup, rule will be deleted which user can notice that it does not appear anymore on current(in this case "Test Environment") context.