Most likely the story is a tale of the two

Used in UN Peacekeeping

The torso area is exposed without a lining

a now bygone division of the US Air Force

or general outdoor use

British Army Cotton Work Coveralls Olive Green - Medium 180/100 Swedish Most likely the story isAt a glance 100% Cotton Material Velcro Front Closure 1 Chest Pocket & 1 Large Hip Pocket Velcro Adjustable Trouser & Sleeve Cuffs Heavy Duty & Hard Wearing Elasticated Back Waistband Shoulder Epaulettes Rank Slides Easy to Wash Solid Olive Green Colour Chest Size: 44" Estimated Size: Medium Regular Label suggests a chest around "100"cm Sleeve Length: 25. 5" Regular Label suggests a height around "180"cm Inside Leg: 30. 5" Total Length: 67" Retro