Navratri is celebrated with fun and religious fervor by Hindus across India. The festival is celebrated twice a year. Chaitra Navratri is celebrated in March-April, while Sharadeya Navratri is celebrated in October - November.
Lord Brahma of the trinity Brahma, Vishnu & Shiva, granted Mahishasura the "buffalo demon," or simply Mahisa (buffalo) a boon that protected him from any man in the world. Empowered by this gift, Mahishasura set out to conquer the world, heaven and the world, and brought about the defeat of Indra king of deities. At the pleading of Indra, the king of the Gods, Lords Brahma, Vishnu and Shiva created Durga, the female through and amalgamation of their own shakti or divine power. Endowed with the trinity's shakti, Durga proved to be a formidable opponent who fought Mahisa for nine days, beheading him on the tenth. The nine nights simply translated Navratri, symbolize the nine days of battle, while the tenth day, Vijayadashami-literally means the victorious tenth day of conquest. Navratri is celebrated to commemorate her victory over the demon, which symbolizes the victory of the good over the evil. This great epic is recounted and celebrated slightly differently in various regions taking on different forms and names. In West Bengal Navratri, and Vijayadashami are respectively celebrated as Durga Puja and Dussehra. In South India the festival includes other female deities an dedicates three days of the festival to Lakshmi, the female archetype of wealth and fortune, and another three to Saraswathi, the female archetype of learning, music and knowledge. In North India it takes the form of the great epic Ramyana where Rama, an incarnation of Vishnu is victorious over the evil king Ravana.
Daksha, the king of the Himalayas and the plains, and his wife, Menaka, were blessed with a beautiful and virtuous daughter called Uma. Since her childhood Uma wanted to marry Shiva. Uma started worshipping Shiva since her childhood. Shiva, being pleased with the worship of Uma, came to marry her. Daksha did not like this tiger-skin clad groom with ash & dirt spread over all of his body. Uma got married to Shiva but was prevented by her father from moving to Kailash, the abode of Shiva. Daksha, later on, arranged for a 'yagna' where everyone except Shiva was invited. Uma, feeling ashamed of the behavior of her father and shocked by the attitude towards her husband, committed Sati (the woman immolates herself in a burning pyre). Shiva came to know about this and went to Daksha's house. He lifted the body of Uma on his shoulders and started dancing madly. With the supreme power dancing, the World was on the verge of destruction. On the request of other Gods, Lord Vishnu came forward as a savior and used his 'Chakra' to cut the Body of Uma into pieces. Those pieces started falling off from the shoulder of the dancing Shiva into different parts of the World. Shiva was finally pacified when the last piece fell off from his shoulder.. Soon after doing this, she was united with the eternity. Therefore, Uma came to be known as Sati. Vishnu revived Uma for a new life, Sati was reborn again. In the second birth, Sati married Lord Shiva and the divine couple lived happily, thereafter. It is believed that Sati comes to stay with her parents for nine days, every year. This is celebrated as Navratri.
The places where the pieces had fallen are known as the 'Shakti Piths' or energy pits, few of these places being Kalighat in Calcutta, Kamakshya near Guwahati among others. Ever since peace was restored, Uma, with her four children, Ganesh, Kartikeya, Saraswati and Laxmi and with her two 'sakhis' - Jaya and Bijaya, comes to visit her parent's home each year during the season of 'Sharat' or autumn when Durga Puja is celebrated.
As per our great epic Mahabharat, Pandavas after wandering in the forest for 12 years hung their weapons on a Shami tree before entering the court of king Virat to spend the last one year in disguise. After the completion of that year on Vijayadashmi the day of Dussehra they brought down the weapons from the Shami tree and declared their true identity. Since that day the exchange of Shami leaves on Dassera day became symbols of good, will and victory.
This festival has immense mythological significance. As per Ramayan, Ram performed "chandi-puja" and invoked the blessings of Durga to kill Ravana, the ten-headed king of Lanka who had abducted Seeta and had charmed life. In order to worship Goddess Durga, Lord Rama needed 108 blue lotus flowers. However, he could manage only with 107. To attain the magical number, he decided to offer one of his eyes, which was lotus-shaped and blue in color, at the Goddess's feet. Satisfied with his devotion Goddess Durga appeared and blessed him. Durga divulged the secret to Ram how he could kill Ravana. Then after vanquishing him, Ram with Seeta and Laxman returned victorious to his kingdom of Ayodhya on Diwali day.
Kautsa, the young son of Devdatt, insisted on his guru Varatantu to accept "gurudakshina", after finishing his education. After lots of persistence his Guru, finally asked for 14 crore gold coins, one crore for each of the 14 sciences he taught Kautsa. Kautsa went to king Raghuraj, who was known for his genorisity and was an ancestor of Rama. But just at that time he had emptied all his coffers on the Brahmins, after performing the Vishvajit sacrifice. So, the king went to Lord Indra and asked for the gold coins. Indra summoned Kuber, the god of wealth. Indra told Kuber, "Make a rain of gold coins fall on the "shanu" and "apati" trees round Raghuraja's city of Ayodhya." The rain of coins began to fall. The king Raghu gave all the coins to Kautsa, who gave 14 crores gold coins to his guru. The remaining coins were lavishly distributed to the people of Ayodhya city. This happened on the day of Dussehra. In remembrance of this event the custom is kept of looting the leaves of the "apati" trees and people present each other these leaves as "sone" (gold).