Bihu (Assamese: বিহু) is the chief festival in the Assam state of India. It refers to a set of three different festivals: Rangali or Bohag Bihu observed in April, Kangali or Kati Bihu observed in October, and Bhogali or Magh Bihu observed in January.The Rangali Bihu is the most important of the three celebrating the Assamese new year and the spring festival. The Bhogali Bihu or the Magh Bihu is the one that is all about food. The Kongali Bihu or the Kati Bihu is the sombre, thrifty one reflecting a season of short supplies.
The Rangali Bihu coincides with Vaisakhi in north India observed by Sikhs and Hindus, and Hindu festivals with similar significance are known by many other names in different parts of India, such as Vishu in Kerala. The other two Bihu festivals every year are unique to Assamese people. Like some other Indian festivals, Bihu is associated with agriculture, and rice in particular.
it has eventually become a very popular urban festival in recent decades. The Bihu Festival involves Bihu folk dance and songs. Bihu is said to be Assam's national festivals and are considered as a very improtant festival of Assam. The Bihus are celebrated by all the Assamese,
Rongali Bihu is also popularly known as Bohag Bihu. This festival indicates the beginning of Assamese New Year, which is around April 15 during the spring season. This signals Hindu solar calendar's first day and New Year is celebrated in various regions such as Bengal, Kerala, Manipur, Orissa, Nepal, Tamil Nadu and Punjab and are called with different names. It is a merry time of feasting for seven long days. The fields are prepared for paddy cultivation and women of the house prepare traditional food called Larus which is made of coconut and rice, Jolpan and pitha which brings in a new charm to the whole season.
In the first day, the cattle is worshipped after washing also called as goru or cow bihu. This is then followed by manuh or human bihu, when people clean themselves and dress in new clothes. Third day after this is indicated as Gosai or Gods bihu. During this time, the Gods' statues are worshipped and are prayed for a smooth and healthy new year.