However, there is not always 1 hour difference because Some countries have non-standard time zones, usually with a 30-minute offset (a few have a 45-minute offset). For example, the time zone in India is five hours and 30 minutes (UTC+5:30) ahead of UTC.
Time zones’ boundaries are irregular mainly because of political factors, and so this has been a subject of criticism. Time zones can be determined by how countries’ and states’ borders are positioned. Individual zone boundaries are not straight because they are adjusted for the convenience and desires of local populations. Moreover, some geographically large countries, such as India and China, use only one time zone but other large countries, such as Russia and the United States, have more than one time zone.