Today, the last day of Bengali month of Poush is Makar Sankranti or Poush Sankranti celebrated as a harvest festival in different names in India. In West Bengal it is known as Poush Parbon, in Gujrat as Uttarayan, in South India as Bhogi, in Punjujab as Lohri. Many Hindu pilgrims gather on this auspicious day at Gangasagarer Mela, the point where Ganges river meets the Bay of Bengal. It is believed that Pilgrims take an early morning dip in the river to eliminate of all their sins and pray to Sun God. To read more about Poush/Makar Sankranti I found this website which is beautifully explained by Sadhguru.
