Pohela Boishakh (Bengali: পহেলা বৈশাখ) is the first day of the Bengali calendar which is also the official calendar of Bangladesh. This festival is celebrated on 14 April in Bangladesh and 15 April in the Indian states of West Bengal, Tripura, and Assam (Barak Valley) by Bengalis regardless of religious faith.

Celebration of Pohela Boishakh traces its roots back to Mughal rule in this region and also the proclamation of tax collection reforms of Akbar.

The festival is celebrated with processions, fairs and family time. The traditional greeting for Bengalis in the new year is শুভ নববর্ষ "Shubho Noboborsho" which is literally "Happy New Year". The festive Mangal Shobhajatra is organized in Bangladesh. In 2016, the UNESCO declared this festivity organized by the Faculty of Fine Arts, University of Dhaka as a cultural heritage of humanity.
Source : Wikipedia*