Actually some of the former British colonies and most of the Americas start the week on Sunday, Muslim World start on Saturday, Maldives on Friday, rest of the planet follows the standard.
That map is just what the Unicode consortium ( a California non-profit) decided should be used on it's standards.
It has zero authority on what day is the fist day of the week outside that and it certainly has not done any real research on what people actually use in all these countries.
Same with ISO 8601 in regards to dates. It's not actually used outside of naming sortable computer files (if even that) and certainly now used in common speech or official documents etc.
Simply put misrepresenting these maps and ISOs by generalizing what they apply to is wrong
We could standadize measurements more than 100 of years ago with the metric system, we can also do this with time and date. ISO 8601 is the future old man.
About that map I didn't search too much for it, if you find a better map it could be a nice new post in this community.
Well, that's the ISO standard, so if you think otherwise, you are wrong :)
Well sorry I don't think SO.
Muslim World start on Saturday
Wait do we? Our firstday is Sunday, but Saturday and Friday aren't numbered (Sabbath and groupingday, respectively) so I couldn't tell you if they're the start or the end of the week.
Sunday comes first in order in calendars shown in the table below. In the Abrahamic tradition, the first day of the week is Sunday. Biblical Sabbath (corresponding to Saturday) is when God rested from six-day Creation, making the day following the Sabbath the first day of the week (corresponding to Sunday). Seventh-day Sabbaths were sanctified for celebration and rest. After the week was adopted in early Christianity, Sunday remained the first day of the week, but also gradually displaced Saturday as the day of celebration and rest, being considered the Lord's Day.
So in Abrahamic religions, first day of week is Sunday, as the day after Sabbath. In Germany, Monday became day one in 1969 (DRG), and 1975 (FRG), respectively.