This day marks the triumph of Lord Rama over Demon king Ravana. On this day, Rama killed Ravana and freed his wife Sita after leading an army of monkeys. Sita was taken by Ravana from Ramas Ashram to avenge the insult of his sister Shoorpanakha who had proposed to marry Ram (or Lakshman) but got her nose cut off by Lakshman when she tried to hurt Sita. As per Ramayan, Ram did Chandi-Puja and invoked the blessings of Durga to kill Ravana. The war against Ravan lasted for ten days. Sita had been returned to her husband Ram and they now make their way to Ayodhya in triumph and glory. Thus, it is on the Diwali day that Lord Ram, the incarnation of Lord Vishnu in the Treta Yug, returned to his capital Ayodhya after the exile of fourteen years.