INDIA, AND ANY SCHEDULE THAT INVOLVES IT
The half hour that breaks every scheduling tool
India is +5:30, not +5 or +6. It also does not observe DST, so the gap to New York changes twice a year without India doing anything.
Somebody proposes a meeting. The tool offers slots on the hour. Your colleague in Bengaluru accepts, and then quietly joins at half past, because the tool has rounded their entire country to something tidier.
Two independent problems, and most tools fail both
The half hour. India is UTC+5:30 — not +5, not +6. A single time zone for a country wide enough for two, set to the meridian between them.
Any system doing whole-hour arithmetic is 30 minutes wrong for 1.4 billion people. Time zone pickers offering only whole-hour offsets literally cannot represent India.
No daylight saving. India has not changed its clocks since the 1940s. So the gap to any observing country moves twice a year, driven entirely by the other side:
| India ↔ New York | India ↔ London | |
|---|---|---|
| Winter | 10:30 hours ahead | 5:30 hours ahead |
| Summer | 9:30 hours ahead | 4:30 hours ahead |
From Bengaluru's point of view, the call with New York moves by an hour twice a year for no reason anyone in India can observe.
Why this feels asymmetric to work with
Because it is. Everyone in an observing country experiences the clock change as something that happened to them — the news mentions it, phones update, there is a shared event.
Colleagues in India experience it as their foreign counterparts arriving an hour early or late, twice a year, with no local cue that anything changed. If nobody says anything, it reads as carelessness.
The fix is one message in mid-March and late October: "Our clocks changed here, so our call is now X your time." It costs nothing and it prevents the whole misunderstanding.
The overlap is narrow and lives at the edges
| Pair | Shared awake window |
|---|---|
| New York ↔ Mumbai | 09:31–12:29 / 19:01–21:59 (3h) |
| London ↔ Mumbai | 14:31–17:29 / 19:01–21:59 (3h) |
| Berlin ↔ Mumbai | 15:31–18:29 / 19:01–21:59 (3h) |
London to Mumbai is genuinely comfortable. New York to Mumbai is not — it sits at the start of the American day and the end of the Indian one, and both ends of it are unsociable.
Teams split across those two converge on a single fixed handover slot rather than hunting for a new time each week, and that is the right instinct.
The practical rules
Write half-hour times explicitly. "18:30 Mumbai," not "around 6." The half hour is the part that gets dropped.
Name the city. "IST" is also Irish and Israel Standard Time.
Re-check the slot at the two US and EU transitions, since those are the only moments it can move.
Do not round. If your tool cannot express +5:30, the tool is wrong, not the country.
Related: Why is India 30 minutes off? · IST to EST
Timezone: World Clock Widget
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Figures on this page are computed from the IANA time zone database. Last generated 2026-08-18.