Offset Time Zones Are Not One of the Standard 24 Time Zones
While most of the world is familiar with time zones that differ in increments of an hour, there are many places in the world that use offset time zones. These time zones are offset by a half-hour or even fifteen minutes off of the standard twenty four time zones of the world.
India, the world's second most populous country utilizes an offset time zone. India is a half-hour ahead of Pakistan to the west and a half-hour behind Bangladesh to the east.
Venezuela's offset time zone was established by President Hugo Chavez in late 2007. Venezuela's offset time zone makes it a half hour earlier than Guyana to the east and a half hour later than Colombia to the west.
One of the most unusual time zone offsets is Nepal, which is fifteen minutes behind neighbouring Bangladesh, which is on a standard time zone.
See full article at http://geography.about.com/od/culturalgeography/a/offsettimezones.htm