Resolves YES if global GDP decreases by 10% according to the following page or an equivalent release from the IMF: https://www.imf.org/external/datamapper/NGDP_RPCH@WEO/OEMDC/ADVEC/WEOWORLD

The decrease does not have to happen over one year. Two years of 6% decreases in a row would resolve YES. The market resolves NO if there is a brief decrease which does not show up on the yearly data (for example, the 2020 recession would not qualify, even if it briefly caused 10% GDP decline).

I believe the last historical example of a global depression was 1929-1932.