Mesha Sankranti is celebrated as Naba Barsha or Pohela Boishakh in West Bengal. Pohela Boishakh is the first day of the Bengali Calendar. Hence Pohela Boishakh is also known as Bengali New Year. Bengali New Year is celebrated in West Bengal and among Bengali communities in Assam and Tripura.
In Assam, Pohela Boishakh is celebrated as Bihu and also known as Assamese New Year.
King Shoshangko of ancient Bengal is credited with starting the Bengali era. The starting point of the Bengali era is estimated to be in 594 in the Gregorian calendar. Hence Bengali year is 594 less than the Gregorian calendar if it is before Pohela Boishakh or 593 less if it is after Pohela Boishakh.