I have found a solution to this problem. Open Ubuntu Software Center,
search for "Language Support," download and install it. This is a language
setting software used in Ubuntu (Unity version). It bears the same UN flag
icon as the language tool in the GNOME control center, but it is a separate
software. When you click and open this software, a dialogue box will pop up
and will ask you if you agree to install the language packs which is
"incomplete." Click yes, and it will install the necessary elements which
might be missing. Then go to regional setting, you will find your region on
the list. Set the desired region and apply it. You should log out and log
in again to make the change take effect.

I think this is only a temporary solution. As Gunnar pointed out, the
language tool in the GNOME control center should be fixed so that the
regional formats can be set from there.

2015-05-08 6:29 GMT-04:00 Gunnar Hjalmarsson <email address hidden>:

> On 2015-05-08 09:31, Saurav Sengupta wrote:
> > My problem, as linked to from comment #12, is that the Region & Language
> > panel does not list India (English). Even if it lists a non-English
> > format such as Korean as mentioned in comment #10, it still does not
> > list any English formats other than the few noted in the OP.
>
> Right. And I think you were close to the truth when you said in a
> comment on the Ask Ubuntu page that gnome-control-center seems to get
> its list from /usr/share/locale-langpack. That's approximately what
> happens, and it's fine when it comes to selecting display languages, but
> it's not correct for selecting regional formats. In other words there
> should be two separate lists, but currently gnome-control-center uses
> the list intended for display languages for both purposes.
>
> My somewhat technical comment was intended for Tim who is an Ubuntu
> GNOME developer. I might propose a fix later on, but I'd like Tim's view
> on which route to take first.
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1440275
>
> Title:
>   Ubuntu GNOME only allows regional format setting for US, UK, Canada,
>   Australia, and NZ
>
> Status in gnome-control-center package in Ubuntu:
>   Triaged
> Status in gnome-desktop3 package in Ubuntu:
>   Triaged
>
> Bug description:
>   I installed Ubuntu GNOME 15.04 Beta 2. I set the system locale to
>   Korean language, which worked okay. When I tried to set regional
>   format (date, time, currency, number, metric, etc.), however, the
>   options are only limited to 5 regions: US, UK, Canada, Australia, New
>   Zealand. I do live in the US, but I want to set the regional format in
>   Korean because that goes with the system language. I currently set the
>   regional format to that of Canada because I am not familiar with US
>   system of yards, feet and pounds. As you can see in the attached
>   screenshot, the date format shown on the middle of the task bar is a
>   mixture of English and Korean (Frankenstein-ish).
>
>   As I browsed through the bug report launchpad site, I found this bug
>   has a long history which dates back to Ubuntu version 9.04. I have
>   installed Ubuntu GNOME 14.04 LTS on my other computer and it does not
>   have the same bug. I guess it has something to do with the newly
>   introduced "systemd"?
>
>   I would very much like to see this bug is fixed ASAP (at least before
>   the release of 15.04 proper version). I love GNOME interface, but this
>   bug annoys me. Regards.
>
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>