Holi is an ancient Hindu religious festival which has become popular with non-Hindus in many parts of South Asia, as well as people of other communities outside Asia. It is celebrated at the approach of the vernal equinox, on the Phalguna Purnima (Full Moon). The festival date, which is determined by the Hindu calendar, varies from year to year on the Gregorian calendar, typically coming in March, sometimes in February. It is primarily observed in India, Nepal, and other regions of the world with significant populations of Hindus or people of Indian origin and Nepalese diaspora.