While exploring Java timezone related API, it was a surprise to me that during the World War II, India(being colony of England) had Daylight Saving Time !
This timezone was in effect from 1-Sept-1942 to 15-Oct-1945. Interestingly, this DST is supported by Java date time API.
DateFormat indiaDtFmt = new SimpleDateFormat("dd/MM/yyyy HH'h'mm");DateFormat gmtDtFmt = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");indiaDtFmt.setTimeZone(TimeZone.getTimeZone("Asia/Calcutta"));gmtDtFmt.setTimeZone(TimeZone.getTimeZone("GMT"));Date worldWarIIDate = indiaDtFmt.parse("02/02/1944 06h30");Date nonWorldWarIIDate = indiaDtFmt.parse("02/02/2006 06h30");System.err.println(gmtDtFmt.format(worldWarIIDate) +" GMT");System.err.println(gmtDtFmt.format(nonWorldWarIIDate) +" GMT");
The above code produces the following output.
1944-02-02 00:00:00 GMT2006-02-02 01:00:00 GMT
So the during the World War II, India was in the timezone +4.30 GMT compared to the normal timezone of +5.30 GMT.
This also mean the horoscopes of the people born in India during the World War II need to take this DST into consideration. These people include celebrities like Ilaiyaraaja,Azim Premji,Amitabh Bachchan etc.
Obviously this well known to Astrologers.Here is one of the links for war-time correction for horoscopes. Another link for war time correction across the world.