How to dispose of the main stage of your rocket cleanly: @ariancespace Ariane 5 User manual says how: after separation from upper stage, main stage is put in flat spin mode by opening lateral venting hole in the hydrogen tank. This causes re-entry and plunge in the Atlantic ocean ('EPC impact' on this map from the User Manual) #CZ5B

The Chinese Long March stage has plunged most probably in the pacific ocean, but the uncertainty on the re-entry window does not exclude it entered the atmosphere over central America or the gulf of Mexico #CZ5B https://www.eusst.eu/newsroom/eu-sst-monitors-reentry-object-cz5b/