FIAP and the PSA have devised rules for images that are specifically entered into the Nature category of their competitions, the PAGB, the L&CPU have agreed to abide by these rules and as a result we at NCPS are bound by them also. This will save any ambiguity for the Selection committee when selecting images for inclusion in external competitions. They are pretty stringent and should you have any questions the committee will be happy to try and answer them.
This link will provide you with a PDF also available on the PAGB website Nature Rules