In Chhatha Puja, perhaps,  Bihar gets its best cultural identity. It is very difficult to find evidences for faith and at the same time it is also impossible to falsify reasons for faith that is religion all about. The sun is worshipped in Chhath puja. It is a universal fact that sun is the source of all kinds of energy and life is simply not possible without it. The human race in its entirety reposes faith in power of the sun. Chhath puja although mainly celebrated by Hindus but it has little religious underpinning. It is based on traditional ethos of agrarian society. Some Muslim families were also reported to be celebrating Chhath festival along with their Hindu brethern.
“Dedication and adoration of sun occurred primarily in agrarian societies. When became a farmer , and thus dependent upon daily and seasonal changes of weather, he often turned to worship the great force that regulated these changes- the light and heat of the sun.  The worship of the sun, is not peculiar to any time or place, received its greatest prominence in ancient Egypt. One of the most important gods of Egyptian religion was Ra, the sun-god, who was considered the first king of Egypt. The pharaoh, said to be the son of Ra, was the sun-god's representative on earth. In later Egyptian religion, under the rule of Ikhnaton, the sun-god Aton gained complete supremacy in what was Egypt's only monotheistic period. In Mesopotamia, where sun worship was also very important, the sun-god Shamash was a major deity and was equated with justice. In Greece there were two sun deities, Apollo and Helios, although there was no institutionalized form of sun worship. The influence of the sun in religious belief also appears in Zoroastrianism, Mithraism, Roman religion, Hinduism, Buddhism, and among the Druids of England, the Aztecs of Mexico, the Incas of Peru, and many Native Americans.” (The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press.
  Although history of sun worship is as old as human civilization but  the chhath festival of Bihar in which Sun God is paid obeisance by the family, friends and local community together in a natural ambiance is a unique among numerous festivals of India. The Chhath puja is of course a native festival of Bihar but it has been celebrated by Bihari migrants working in different parts of India & abroad. The festival  is getting prominence not only in India but abroad too.  The festival continues for four days.  The festivity started from Diwali continues till Chhath. Almost all educational and other government establishments in Bihar and Jharkhand are closed from on the eve of Chhath.
The festival is celebrated at river banks, ponds, wells and other sources of water. The sun is paid obeisance by holding bamboo soop filled with Bananas, coconuts, sugarcanes, other seasonal and local fruits, turmeric and ginger plants, pakwans (home sweets) made of flour etc. by the fasting person generally a lady (parvaitin/worshipper) while standing in water and facing the sun and family members, friends and relatives give arghya by pouring little water and or milk in front of soop held by worshipper.  Soops  are carried from home to above water sources and back in a bamboo basket. The worshipper observes a complete fasting of 36 hours. The obeisance is first paid to the setting sun in the evening and obeisance is paid to the rising sun in the next morning. 

In Chhath puja setting sun is worshipped first and rising sun later. Message of a humane society  is loud  and clear.

The festival has great significance for all of us.  The festival reminds our harmonious relationship with nature. It reminds us the importance of we- feeling and sharing joy and happiness together. It teaches us great lessons in community involvement in cleaning and decorating roads, ghats, surrounding areas apart from own houses.  Prolonged fasting of 36 hours by the worshipper signifies her highest reverence to the deity which is the source of all energy and genesis of life on this earth. Ethos of the festival lies in we feeling and love for nature. The festival is ritual free and simple. The rich and the poor celebrate Chhath puja alike as all are bound by its simplicity.  
  The message of Chhath is our real tradition carried since ancient days. We had the honour of guiding and preaching the world. We  had world famous ancient seat of higher learning like Nalanda and Vikramshila.  We initiated great egalitarian and progressive  traditions like Buddhism and Jainism around 2000 years earlier. We developed traditions of worshipping nature and our people living closely with nature developed harmonious relations with it. 

(Image: courtesy Jagran post)