Diwali, the “festival of lights” is the most important festival for Hindus around the globe. Over the years, ways of celebrating Diawli might have changed but what has not changed is the spirit of gaiety and vivacity, lights and candles, sweets and gifts. Diwali is ingrained in the souls of Indians. This is the festival signifying the victory of good over evil. Diwali wards off the darkness and welcomes light into life. Diwali is an occasion for cheerfulness and togetherness. This is an occasion for young and the old, men and women, rich and poor - for everyone to celebrate. Diwali is celebrated 20 days after Dussera, on Amavasya - the 15th day of the dark fortnight of the Hindu month of Ashwin (Aasho) (Oct/ Nov) every year. The First day is called Dhanteras or Dhantryaodashi, which falls on the thirteenth day of the month of Ashwin. The Second day is called Narka-Chaturdashi or Chhoti Diwali that falls on the fourteenth day of the month of Ashwin. 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. 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.
Legends

Main Legend:

In the north, particularly in Uttar Pradesh, Punjab, Haryana, Bihar and the surrounding areas, Diwali is the day when King Rama`s coronation was celebrated in Ayodhya after his epic war with Ravana, the demon king of Lanka.
By order of the royal families of Ayodhya and Mithila, the kingdom of which Sita was princess, the cities and far-flung boundaries of these kingdoms were lit up with rows of lamps, glittering on dark nights to Welcome home the divine king Rama and his queen Sita after 14 years of exile, ending with an across-the-seas war in which the whole of the kingdom of Lanka was destroyed. Second Legend: In rural areas, Diwali signifies Harvest Festival. Diwali which occurs at the end of a cropping season has along with the above custom, a few others that reinforce the hypothesis of its having originated as a harvest. Every harvest normally spelt prosperity. The celebration was first started in India by farmers after they reaped their harvests. They celebrated with joy and offered praises to God for granting them a good crop. Third Legend: Narakasura, a monster, ruled the kingdom of Pradyoshapuram. He was a trouble-maker to the gods and the pious sages and would disturb their penance or create havoc during the rituals. To prove his power, Narakasura usurped some territory of Aditi, (the king of Suraloka and a relative of Satyabhama, Lord Krishna`s wife).
Vexed with this harassment, Indra and other gods approached Lord Krishna and pleaded with him to protect them from the demon "Narakasura". Satyabhama appealed to Krishna to give her the golden chance to destroy Narakasura, as Narakasura was given a curse that he would be killed by a woman. Krishna granted her a boon to fight with Narakasura. With Krishna as the charioteer, Satyabhama entered the battle field and killed the demon, Narakasura. The killing of Narakasura was a victory of good over evil. It is interesting to note that Bhudevi, mother of the slain Narakasura, declared that his death should not be a day of mourning but an occasion to celebrate and rejoice. Since then, Deepavali is being celebrated by people every year with joyous celebrations with lot of fun and frolic, and fire works. Fourth Legend: On this day Mother Lakshmi emerged from the ocean of milk called the Ksheer Sagar. She brought with Her wealth and prosperity for mankind. On that day, Lakshmi Pooja was performed to honour Her and as such, every year on Diwali day, Hindus perform Her prayer and worship. The making and distribution of various sweets and total vegetarian foods are the order of the day. This practice is alive and well to this very day. Many people believe that Lakshmi, the Goddess of wealth and good fortune, visit the homes of devotees on this day. Worship of Lakshmi is performed in the evening.