The month-long Swasthani Brata Katha and Madhav Narayan festival began on Thursday.
The festival begins on Paush Shukla Purnima (full-moon day) and concludes on Magh Shukla Purnima according to the Nepali calendar.
Many Hindus, both men and women, observe a fast for the entire month during the festival. Family members gather around and recite the Swasthani Brata Katha in the evenings.
Devotees took a holy dip at Gokarna and Pashupati of Kathmandu, Hanuman Ghat of Bhaktapur and other places on Thursday.
Meanwhile, the month-long Madhav Narayan fair began on the banks the Shali River in Sankhu in the northeastern part of Kathmandu.