The festival of Navratri is celebrated all over the country in different ways. For Bengal and its inhabitants it's the time of Durga Puja - a time for laughter, beauty, food and celebration; Ma Durga has come home.
This autumnal festival serenades Ma Durga, the goddess of shakti (Ultimate Power), who destroyed the evil asura (demon) to bring back peace on earth.
Ma Durga leaves her husband Shiv's abode and sets off with her children Ganesh, Lakshmi, Saraswati and Kartik for her father's house which is celebrated as Navratri.
On the sixth day of Shashthi, Ma Durga reaches her father's home. It's the day when the city of Kolkata lights up. Every road and every path in Kolkata leads to a pandal, housing the goddess. From then till the tenth day of Dashami, neither the city nor Maa Durga sleeps.
Finally on Dashami, with great sorrow but with the hope that she will be back soon, Maa Durga is bid adieu and immersed in the Ganges. With everyone praying for good health and blessings till the Goddess comes again next year, Durga Puja comes to an end.
BabyKorn
The image of Goddess Durga represents destruction of evil and protection of good and emphasizes the need to keep one's animal instincts under control.