[tz] Indian Continent

Guy Harris gharris at sonic.net
Mon Oct 12 20:54:38 UTC 2020

On Mon, Oct 12, 2020 at 12:16 PM Bharat Adur <bharatadur at gmail.com> wrote:

> We find for India there is certain bias taken by some individuals in a country which has such a large population and its Indian Standard Time (IST UT= 5hours 30 minutes), which is accepted by National Physical Laboratory (NPL),New Delhi  and Astronomical Society of India.

...and which is the time for the tzdb region with the ID "Asia/Kolkata" - 5 hours 30 minutes ahead of UTC, abbreviation "IST".

So the tzdb *does*, in fact, support Indian Standard Time, using the tzdb ID "Asia/Kolkata".

> our norm of 1970 cannot be acceptable to Modern India

The only "norm" of 1970 is that the tzdb doesn't create new zones for regions that differ *before* 1970.  If something changes *after* 1970, we'll add a new zone if necessary.  It doesn't mean that the tzdb is inherently out-of-date, with nothing that happened *after* 1970 being supported.

> hence its our humble request you to consider IST  UT= 5hours 30 minutes.

We already considered it and support it, with the tzdb ID "Asia/Kolkata".

> and if you desire we can send you at least 50 cities.

There are several significant cities in the United States Pacific Time Zone; however, the tzdb has only one entry for that zone, with the ID "America/Los_Angeles".  There is no entry with the ID "America/San_Francisco"; even though I live closer to San Francisco than to Los Angeles, this is not a problem for me.  There also aren't any entries with the ID "America/San_Diego", "America/Portland", "America/Seattle", etc..

The tzdb does *not* create multiple entries for a given zone so that every city in that zone appears in a tzdb ID for a zone.  A good time zone selector will allow the user to specify a city name and will look up the tzdb ID appropriate for that zone, e.g. for Bangalore/Bengaluru, Delhi, Mumbai, etc., it will select Asia/Kolkata.

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