The 14th Day of the dark half of Aashwayuja to the 2nd day of the bright half of Kaartik.
The word "Diwali" is derived from the Sanskrit word "Deepavali" - Deepa which means light and Avali which means a row, so it is literally a row of lights. Diwali is celebrated 20 days after Dussera, on Amavasya - the 14th day of the dark fortnight of the Hindu month of Ashwin (Aasho) (Oct/ Nov) every year. Even the humblest of huts are lighted by rows of diyas (clay lamps). At 6PM puja is done in temples or at home.
There are many legends pertaining to Diwali one relates the story of king Dashratha who had three wives 1. Kaushalaya, 2. Keykayee and 3. Sumintra and four sons Rama, Bharat, Laxmana and Shatrughan. Rama was the son of Queen Kaushalaya and Bharat was the son of Queen Keykayee. Rama being the eldest was heir apparent to the throne and it was the desire of King Dasharatha that he is. Keykayee on the other hand being manipulated by her Hump-Backed servant wanted Bharat to be the next King. King Dashratha who was bound by two wishes granted to Keykaye who had nursed him back from near death on the battlefield many years earlier, had no choice when Keykaye went to him and demanded that Rama be sent into exile for the period of fourteen years. During that time Lord Rama with Sita his wife and Laxmana at his side visited many ashrams and when Sita was kidnapped by the evil Ravana the two brothers set out on a path towards Lanka the island on the southernmost tip of India. On the way he slew many demons and made many close friends the most dearest of all is Hanuman who with his many powers helped Lord Rama selflessly. Diwali marks their victorious return to Ayodhya the kingdom of Lord Rama. The people of Ayodhya, overwhelmed with joy, welcomed their beloved Rama with great jubilation and illuminated the entire city all the way to the forest. Evil has been conquered, good has triumphed.
People pay respect, honor and homage to Mother Lakshmi the Goddess of wealth and prosperity, who is also the consort of Lord Vishnu by lighting earthen diyas and decorating their houses to welcome her. The lighting of lamps is a way of paying obeisance to the Godess for attainment of health, wealth, knowledge, peace and fame. Diwali is also marked as the beginning of the Hindu New Year and as a brand new beginning for all. Lord Ganesh the elephant-headed son of Lord Shiva and Parvati and the symbol of auspiciousness and wisdom is also worshipped in many Hindu homes. Diwali is celebrated for five days, each day having it's own significance.
THE FIVE DAYS OF DIWALI
The First day is called Dhanteras or Dhantryaodashi, which falls on the thirteenth day of the month of Ashwin. The word "Dhan" means wealth. This day has great importance for rich community. It is believed that sixteen year old son of King Hima according to his horoscope was to die on the fourth day of his marriage by a snake-bite. So on that particular fourth day of his marriage his worried wife lighted innumerable lamps all over the place and laid all the ornaments and gold and silver coins in a big heap at the entrance of her husband's boudoir. And she went on telling stories and singing songs through the night. When Yama the god of death arrived there in the guise of a Serpent he was bedazzled by the bright lights thus blinded by the overwhelming brilliance he could not open his eyes and thus he could not enter the Prince's chamber. So he climbed on the heap of the ornaments and coins and sat their whole night listening to the melodious songs. In the morning he quietly went away. Thus the wife saved her husband and since then this day of Dhanteras came to be known as the day of "Yamadeepdaan" and lamps are kept burning throughout the night in adoration to Yama, the god of Death.
The Second day is called Narka-Chaturdashi or Chhoti Diwali that falls on the fourteenth day of the month of Ashwin. The story related to this day is about King Bali, ruler Paataala (the netherworld) who had extended his Kingdom far and wide even covering the earth. His vastly spreading conquests and enormous power had become a threat to the gods and the universe itself. In order to curb his powers Lord Vishnu in the guise of a dwarfish Brahmin by the name of Vaaman visited him and begged him to give him only that much land which he could cover with his three steps. King Bali known for his charity proudly granted him his wish. Vaaman then grew into a gigantic form and with his first step he covered the entire heaven and with the second step the earth and asked Bali where to put his third step. Bali offered his head and putting his foot on his head Vishnu pushed him down to the netherworld. But for his generosity Lord Vishnu allowed him to return to earth once a year to light millions of lamps to dispel the darkness and ignorance and spread the radiance of love and wisdom.
The Third day of the festival of Diwali is the most important day of Lakshmi-Puja, which is entirely devoted to the propitiation of Goddess Lakshmi. This day is also known by the name of "Chopada-Puja". The day of Lakshmi-Puja falls on the dark night of Amavasya. It is believed that on this auspicious day Lord Krishna discarded his body. One more interesting story related to this day is of a small boy called Nichiketa who believed that Yama, the god of Death was as black as the dark night of amavasya. He on this day met Yama in person and was puzzled seeing Yam's calm countenance and dignified stature. Yama explained to Nichiketa on this day of amavasya that by only passing through the darkness of death, man sees the light of highest wisdom and then only his soul can escape from the bondage of his mortal frame to mingle with the Supreme Power without whose will nothing moves in the world. And then Nichiketa realised the importance of worldly life and significance of death. Nichiketa's all doubts were set at rest and he whole-heartedly participated in Diwali celebrations.
The Fourth day is called Padwa or VarshaPratipada that marks the coronation of King Vikramaditya and Vikaram-Samvat was started from this Padwa day. Govardhan-Puja is also performed in the North on this day. The people of Gokul used to celebrate a festival in honor of Lord Indra and worshipped him after the end of every monsoon season. But one year the youthful Krishna stopped them from offering prayers to Lord Indra. The infuriated Indra sent a deluge to submerge Gokul. But Krishna saved his beloved Gokul by lifting up the Govardhan Mountain as an umbrella over all the people.
The Fifth and final day of Diwali Festival is known by the name of "Bhaiya-Duj" This day is observed as a symbol of love between sisters and brothers. It is believed that on this day Yamraj -the god of death visited his sister Yami and she put the auspicious till on his forehead, they ate talked and enjoyed together and exchanged special gifts as a token of their love for each other and Yamraj announced that anyone who receives tilak from his sister on this day will never be thrown. Since then it became imperative for the brother to go to his sister's house to celebrate Bhaiyaduj.