Dhanteras is a religious Hindu day that is observed in India as the festival of Diwali, and in Nepal as the festival of Tihar. It falls on the 13th lunar day in the month of Karthik, which corresponds with the Gregorian’s months of October and November. On that day, the Hindu god of medicine, Dhanvantari, is widely worshipped – praying to him for a long healthy life, free of diseases.