All Hindi characters are displayed, but why are they not rendered properly?
IndiX system uses an OpenType font to render Indic script characters, as it is the most suitable font format for Indic scripts. If you use some other kind of font, for example a TrueType font or a Bitmap font, then the font does not have enough information that is required to render Indic script text properly. So it is recommended to use only OpenType fonts for Indic scripts. Also, in case you are already using an OpenType font, please update your glibc.