The timezone IST in India

Only 1 nationwide time zone

Standard time:	UTC +5.5	India Standard Time (IST)
Daylight saving time:	UTC +6.5	discontinued 1945

India has an east-west extension of 27.3 degrees of longitude. Given the country's location in South Asia, this corresponds to about 2800 kilometers. At this extension, from a purely geographical point of view, 2 time zones would be envisaged, since their optimal distance is 15 degrees of longitude. The position of the sun in the west of the country differs from that in the east by 109 minutes. This means the sun rises and sets 109 minutes later in the west than in the east.

No more daylight saving time in India

Due to the sun's orbit around the equator, the days are longer in summer (June to September in the northern hemisphere). Countries that switch to daylight saving time in the summer months align the daylight phase with the human rhythm. Unused bright morning hours are thus shifted into the evening (more information on daylight saving time here).

Due to the relative proximity to the equator, the impact in India is not particularly large. New Delhi is only 3,200 km from the equator. A day in midsummer would then not last from 05:22 to 19:23, but from 06:22 to 20:23. The effect would be quite noticeable in the evening, but the sun rising later in the morning falls at a time when many people are already awake. Thus, in 1945, the decision was made to finally abandon daylight saving time in India.

Changes in Daylight Saving Times

In India Daylight Saving Time has been observed since 1941 until 10/14/1945.