In a fresh Ubuntu, not having the locales setup, it shows warning every time while installing any software/library and while stopping/restarting too.
The simple way to setup the locales you need is…
e.g. “en_IN UTF-8″

Step 1

Edit or Create the file /var/lib/locales/supported.d/local and add the required local in the file as…
[source:ruby]
en_IN UTF-8
[/source]
you can add more locales in new lines.

Step 2

reconfigure your system’s locales by issuing the command
[source:ruby]
dpkg-reconfigure locales
[/source]

Thats done!