New Year is the time or day currently at which a new calendar year begins and the calendar's year count increments by one. Many cultures celebrate the event in some manner. In the Gregorian calendar, the most widely used calendar system today, New Year occurs on January 1. This was also the first day of the year in the original Julian calendar and the Roman calendar. Other cultures observe their traditional or religious New Year's Day according to their own customs, typically because they use a lunar calendar or a lunisolar calendar. Chinese New Year, the Islamic New Year, Tamil New Year, and the Jewish New Year are among well-known examples. India, Nepal, and other countries also celebrate New Year on dates according to their own calendars that are movable in the Gregorian calendar.