In the "pūrṇimānta māna" Hindu lunar calendar used in most parts of the Indian subcontinent, the lunar month starts on the day following the full moon or "purnima" and therefore Amāvásyā always falls in the middle of the month. However, in the "amānta māna" calendar used in some places, the lunar month starts on the day of the new moon, making Amāvásyā the last day of the lunar month in those places. Many festivals, the most famous being "Diwali" (the festival of lights), are observed on Amāvásyā. Many Hindus fast on Amāvásyā.