The discovery of the Ozone hole was first made over?

The severe seasonal thinning of stratospheric ozone was first detected over Antarctica, giving rise to the term ozone hole.

The Arctic does show ozone loss, but its milder, less persistent depletion was recognised only later and never matched the Antarctic scale.

Near the Equator ozone stays relatively stable, so no hole forms over the tropical belt.

The tropics likewise experience no such collapse because the cold conditions needed for rapid ozone destruction are absent there.

The extreme cold of the Antarctic winter forms polar stratospheric clouds on which chlorine reactions destroy ozone.

British Antarctic Survey scientists reported this dramatic springtime loss in the mid 1980s.