What is the theme of World Hydrography Day 2021?

Hydrography - contributing to the United Nations Ocean Decade

One hundred years of international cooperation in hydrography

Hydrography-enabling autonomous

None of these

World Hydrography Day is observed on June 21 every year to raise awareness about hydrography and the essential role that it plays in improved knowledge of the seas and oceans.
Theme 2021: One hundred years of international cooperation in hydrography
Theme 2022: Hydrography - contributing to the United Nations Ocean Decade