A part of Gaura-purnima celebrations, Ganga-puja and immersion of ashes of departed souls is performed. Devotees offer puja to Ganga, something that Lord Chaitanya Mahaprabhu liked very much, take bath in her holy waters and also fetch a pot of water for Gauranga Mahaprabhu’s abhisheka on Gaura-purnima.
Ganga-devi emanates from the lotus feet of the Lord. She is flowing throughout the universe bestowing mercy to all, but in Navadvipa-mandala, but as stated by Srila Bhaktivinoda Thakura, she distributes special mercy not available anywhere else. Her divine waters in Navadvipa-mandala bestow Gauranga-prema, love for Lord Gauranga.
Just like a caring mother, Ganga-devi nourishes and protects the tender Bhakti creepers of those who take shelter of her by bathing in her sacred waters and worship her.
Immersion of the ashes of departed souls in Ganga helps them get liberated from all sins and awards them a birth to continue Krishna-bhakti.