Vijayadashami also known as Dussehra, Dasara or Dashain or Mohani , is a major Hindu festival celebrated at the end of Navaratri every year. It is observed on the tenth day in the Hindu calendar month of Ashvin, the seventh month of the Hindu Luni-Solar Calendar, which typically falls in the Gregorian months of September and October.
Vijayadashami is observed for different reasons and celebrated mostly in Nepal and India.,southern, eastern, northeastern, and some northern states of India, Vijayadashami marks the end of Durga Puja, remembering goddess Durga's victory over the buffalo demon Mahishasura to restore and protect dharma.
In the northern, central and western states, the festival is synonymously called Dussehra (also spelled Dasara, Dashahara). In these regions, it marks the end of Ramlila and remembers god Rama's victory over Ravana. On the very same occasion, Arjuna alone decimated more than 1,000,000 soldiers and defeated all Kuru warriors including Bhishma, Drona, Ashwatthama, Karna and Kripa, a significant example of victory of good (Dharma) over evil (Adharma). Alternatively, it marks a reverence for one of the aspects of goddess Devi, such as Durga or Saraswati.
Vijayadashami celebrations include processions to a river or ocean front that involve carrying clay statues of Durga, Lakshmi, Saraswati, Ganesha and Kartikeya, accompanied by music and chants, after which the images are immersed in the water for dissolution and farewell. Elsewhere, on Dasara, towering effigies of Ravan, symbolising evil, are burnt with fireworks, marking evil's destruction. The festival also starts the preparations for Diwali, the important festival of lights, which is celebrated twenty days after Vijayadashami.
Ravana kidnaps Sita and takes her to his kingdom in Lanka (present day Sri Lanka). Rama asks Ravana to release her, but Ravana refuses; the situation escalates and leads to war. After performing severe penance for ten thousand years, Ravana receives a boon from the creator-god Brahma; he could henceforth not be killed by gods, demons, or spirits. Lord Vishnu incarnates as the human Rama to defeat and kill him, thus circumventing the boon given by Lord Brahma. A deadly and fierce battle takes place between Rama and Ravana in which Rama kills Ravana and ends his evil rule. Ravana has ten heads; the killing of one who has ten heads is called Dusshera. Finally, Dharma was established on the Earth because of Rama's victory over Ravana. The festival commemorates the victory of Good over Evil.
In the Mahabharata, the Pandavas are known to have spent their thirteenth year of exile in disguise in the kingdom of Virata. Before going to Virata, they are known to have hung their celestial weapons in a Shami tree for safekeeping for a year. Bhima kills Kichaka.
Hearing about the death of Kichaka, Duryodhana surmises that the Pandavas were hiding in Matsya. A host of Kaurava warriors attacks Virata, presumably to steal their cattle, but in reality, desiring to pierce the Pandavas' veil of anonymity. Full of bravado, Virata's son Uttara attempts to take on the army by himself while the rest of the Matsya army has been lured away to fight Susharma and the Trigartas. As suggested by Draupadi, Uttar takes Brihannala with him, as his charioteer. When he sees the Kaurava army, Uttara loses his nerve and attempts to flee. Then Arjuna reveals his identity and those of his brothers'. Arjuna takes Uttar to the tree where the Pandavas hid their weapons. Arjuna picks up his Gandiva after worshipping the tree, as the Shami tree safeguarded the Pandavas’ weapons for that complete year. Arjuna reties the thread of Gandiva, simply drags and releases it – which produces a terrible twang. At the same point of time, Kaurava warriors were eagerly waiting to spot Pandavas. Dispute talks took place between Karna and Drona.
Karna told Duryodhana that he would easily defeat Arjuna and does not feel threatened by Drona's words since Drona was intentionally praising Arjuna, as Arjuna was the favourite student of Drona. Ashwathama supports his father by praising Arjuna. Then Arjuna arrives to the battlefield.
Eager to defend the land that had given him refuge, Arjuna engaged the legion of Kaurava warriors. The battle starts between Arjuna and the entire Kuru army. All the warriors including Bhishma, Drona, Karna, Kripa and Ashwathama together attacked Arjuna to kill him, but Arjuna defeated all of them multiple times simultaneously. During the battle, Arjuna also killed Sangramjita, the foster brother of Karna, and instead of taking revenge for his brother, Karna fled in order to save his life from Arjuna. Karna tried to fly away from Arjuna but he could not since Arjuna invoked Sammohanaastra which made the entire army fall asleep. This is the war in which Arjuna proved that he was the best warrior in the world at his times. In this way, Arjuna alone defeated the entire Kuru army consisting of 1,000,000s of soldiers; Duryodhana, Dushyasana, Shakuni and Maharathis : Bhishma, Drona, Karna, Kripa and Ashwatthama. One of the names of Arjuna is Vijaya – ever victorious. This incident took place on the same day in which Lord Rama killed Ravana. As it was Arjuna's day, the day also became popular as "Vijaya Dashami"