21. The expert from Poland, in his capacity of Chair of the Informal Working Group on Visibility, Glare and Levelling (IWG VGL), reported on the IWG activities (GRE-76-19). The expert from OICA, Secretary to IWG VGL, proposed to modify the Terms of Reference (ToR) of IWG VGL (GRE-76-20-Rev.1). GRE adopted the revised ToR, as laid down in Annex III to the report.