The birth of Lord Krishna was the incarnation of Lord Vishnu. This incarnation was for ending the reign of evil Kansa whose atrocities had been troubling mankind. Janmashtami is observed is the Shravan maas on the eighth day, the birth falls in Rohini nakshatra that is in the months of August-September.
It is ceremonious to rain heavily on the night lord Krishna was born. It is said that Lord Krishna was born on a stormy night on a rainy day. All rituals and puja happen after the birth of Krishna i.e. after midnight.
Krishna Janma is celebrated with great enthusiasm throughout the country. The preparations begin much before the day of Janmashtami. A cradle is decorated with flowers and decorations. New clothes and jewellery is made to order for Bal Krishna.
Celebrations resound for two days. The first day is the day before midnight. Before Janma all the enthusiast devotees throng temples and sing bhajans and songs signifying Krishna Janma.
After the birth, the ceremony of child birth and bhog (dishes offered after puja) and aarti is done. The bhog consists of 56 varieties of food. People who observe fast on Janmashtami break it with Prasad. Next day after birth, is Kalashtami.
The fervour of the festival is most in Mathura and Vrindavan which have been mentioned to be the places of Krishna leela in the mythology. The zeal among the people is much more than at any other place. People place the baby idol of Lord Krishna in the Grabh Griha (where he was born) before midnight.
Devotees keep singing the bhajans and aartis all through the night and stories depicting Krishna Leela are chanted to add to the flavour of the night. Post birth, Abhishek is done with milk, ghee, curd butter, water and flowers. Some also prepare Panchamrit (milk, ghee, oil, honey and Gangajal) for the Abhishek.
Rasleela is the traditional dance performed by all the devotees. Another ceremony performed is Dahi Handi. Dahi Handi is an earthen pot filled with curd hanged at a height. This pot is meant to be broken by young men. These men symbolize Bal Krishna and his friends. The Dahi handi is specially celebrated in Mathura, Vrindavan, Dwarka and Mumbai.
To show the various life stages of Shri Krishna, tableaux are taken out. Children, men and women dressed in colourful traditional ghagra and cholis, dhoti kurta sing and dance along the floats. People stop and welcome the tableaux at various places. Some also perform aarti to the idols.
It is a festival observed around the world. The chain of temples like ISKON (International Society for Krishna Consciousness) which work towards preaching teachings of Lord Krishna, observe Janmashtami. The Hindu community across the globe comes together and celebrates the birth of Lord Krishna.