Hindu Holidays Rules
Hindu holidays recurrence rules are either based on the Hindu Lunar Calendar or the Hindu Solar Calendar. Most Hindu holidays are based on the Lunar Calendar.
Hindu Lunar holidays are based on a lunar month-day-time triplet.
Deepavali in Singapore
The Leap day if exists option is used for Hindu public holidays of the paraviddha type (such as Deepavali and Diwali) .
There are 2 types of Hindu Solar holidays:
Most are simply based on a solar month-day pair.
Tamil New Year, India
But some also depend on the Nakshatra: