Chhatt Puja is celebrated in certain states in North India namely Eastern Uttar Pradesh, Jharkhand, and Bihar. It is also popular in Nepal. It is a Vedic festival that is dedicated to the Sun God (Lord Surya) and Chhathi Maiya (another name for Goddess Usha and a known sister to Lord Surya).
The festival is called ‘Chhath‘ because it means the number 6 in Hindi or Nepali. The festival is celebrated on the 6th day of the month of Karthika.