Flag of Sikkim, in use from 1967 to 1975
Own work based on: 

Mario Fabretto: La simbologia buddista nelle bandiere del Sikkim. In: Vexilla Italica. Band 61, Nr. 2, 2006.
UnknownUnknown  (flag design), first version of SVG file uploaded by Nichalp, subsequent edits by User:Goran_tek-en and AnonMoos