Mahaparva Chhath Puja

The word chhath means sixth and the festival is celebrated on the sixth day of the month Kartika of the Hindu lunar Bikram Sambat calendar.

Chhath is a Hindu festival dedicated to the Sun god and his wife Usha in order to thank them for bestowing the bounties of life on earth.
The Goddess who is worshipped during the famous Chhath Puja is known as Chhathi Maiya (also known as Usha, wife of the sun god).

Chhath is an ancient Hindu festival historically native to the Indian subcontinent, more specifically, the Indian states of Bihar, Uttar Pradesh,West Bengal, Jharkhand, and the Nepalese provinces of Madhesh and Lumbini
Prayers during Chhath puja are dedicated to the solar deity, Surya, to show gratitude and thankfulness for bestowing the bounties of life on earth and to request that certain wishes be granted.
Chhathi Maiya, the sixth form of Devi Prakriti and Lord Surya’s sister is worshipped as the Goddess of the festival.
It is celebrated six days after Deepavali, on the sixth day of the lunar month of Kartika (October–November) in the Hindu calendar Vikram Samvat
The rituals are observed over four days.
They include holy bathing, fasting and abstaining from drinking water (vrata), standing in water, and offering prasad (prayer offerings) and arghya to the setting and rising sun.
Some devotees also perform a prostration march as they head for the river banks

Chhath puja is dedicated to the sun god Surya.
The sun is visible to every being and is the basis of life of all creatures on earth.
Along with the Sun God, Chhathi Maiya is also worshipped on this day.
According to Vedic astrology, Chhathi Maiya (or Chhathi Mata) protects the children from diseases and problems and gives them long lives and good health.
As per legends, Chhath Puja stems from the early Vedic period, where sages would fast for days and perform the puja with mantras from Rigveda.
It is believed that Chhath Puja was also performed by Karna, the son of Lord Surya and the king of Anga Desh, which is the modern-day Bhagalpur in Bihar.
According to another legend, Pandavas and Draupadi also performed the Puja to overcome obstacles in their lives and reclaim their lost kingdom
For the people from Bihar and other close by areas, Chhath Puja is considered as Mahaparva