The Parvaitin or the main worshipper has to obey the strict rules and arduous rituals. The person has to undergo an asceticism and isolation during the four days of festival. The celebrations of four action pact days of Chhath Puja are worthy of mention.

The first day of the celebration of Chhath starts with a holy dip into the sacred River Ganges (or any nearby river). Devotees carry the water and prepare offerings using the water of the Ganges. The houses where the pujas take place have to be thoroughly cleaned. Worshipper is only allowed to take one meal on this day. Some of the places know this tradition as “kaddu bhat”. Parvaitin generally eats kaddu, channa dal and arwa chawal.

On Panchami, the day before Chhath, parvaitins fast from daybreak to sundown. They are not even allowed to drink water. The Parvaitin takes food after she offers prayers and Prasad to Surya after the sunset. Racio-kheer, puris and bananas are circulated among the family members and friends. Friends are invited to the homes to share Prasad. Later on, the Parvaitin goes on a fast for almost 36 hours. Parvaitins don't even take water during these 36 hours.

Evening offerings (Sanjhiya Arghya): The day is mainly spent in preparing Prasad at home. Thekua (a fried cookie like food) and kasara (laddo made of rice powder) are the most important offerings. Households honor and pray to the setting sun by offerings (Aragh) and to do that all the family members visit riverbanks or nearby pond or common large water body along with Parvaitins.

It's not only Parvaitins or the family members, but onlookers and numerous participants are keenly interested to partake in the carnival. The blessings of the Sun God and worshippers are rewarding. Singing traditional folk songs during the occasion is an integral part of the Chhath celebration. The tradition is carried forward orally from mothers and mother-in-laws to daughters and daughter-in-laws.

The folk songs truly depict the cultures and social structures of Bihar and Uttar Pradesh. Even though the latest trend is to play Bollywood hit numbers during the festival but the traditional folk songs are the vital parts of the Chhath puja celebration and is still going strong with a great degree of purity and holiness. Bihar comprises of three prime linguistic regions namely Maithili, Magadhi and Bhojpuri. All the various norms and dialects of these places vary a lot. However, the underlying meanings of the folk songs are almost same and all these songs are related to Chhath. Even though there is a fundamental similarity in the celebration and rituals of Chhath festival but rituals vary significantly from one region to the other and even between the families.

Kosi: It's a colorful event of Chhath festival and is held during the third night. An awning is made with five sugarcane sticks to place lighted clay lamps underneath. The existence of five sticks exemplifies the human body made of Panchatattva (The five great elements- earth, water, fire, air and ether). This ritual is mainly performed in the family where a recent marriage ceremony or childbirth has taken place. This is basically a symbolic rite. The lighted earthen lamps signify and imply that human beings are sustaining due to the energy generated by the Sun. The ritual is performed during the period of late evening on the third day while making the offerings to the setting sun.

Bihaniya Aragh, the next morning offerings: It is the time to make offerings (aragh) to the rising sun. Devotees along with friends and family members travel to the banks of the river before sun rises. The festival ends with breaking the devotional fasting of Parvaitins and all the friends who visit the houses to share Prasad. It's an enticing and charming experience to watch the vista around when the Chhath is celebrated at the crack of the dawn on the banks of the river. It's a place where devotees can witness the blend of the ancient traditions and modern Indian cultures. The river Ganges is worshipped as mother after aragh.