The nation have started celebration of ‘Pohela Boishakh’, the first day of Bengali New Year 1423, on Thursday amid much enthusiasm and traditional gaiety as millions of people expected to join the ‘Nabobarsho’ festivities across the country.The programmes of the day started at dawn, in the city with the musical soiree of Chayanat, a leading cultural organization of the country at Ramna Batamul.President Abdul Hamid and Prime Minister Sheikh Hasina issued separate messages greeting the countrymen marking the day.The day is a public holiday.