Since morning, people were busy decorating their houses with 'diyas' (earthen lamps) and colourful 'rangolis', and exchanging sweets with neighbours and relatives.
Enthusiastic children started bursting crackers since morning, while the elderly began the day offering prayers at temples.
Markets were decked up to welcome the large number of buyers, who rushed to nearby shopping centres for last minute purchases, especially sweets and crackers.
Many, mostly the youngsters, took to social networking site Facebook to wish a 'Happy Diwali' to friends and some of them used the platform advising their friends to follow safety norms while bursting crackers.
Police and Delhi Fire Service Department personnel were on their toes fine-tuning arrangements to ensure an "incident-free" Diwali.
Security was strengthened across the city, particularly in markets and other crowded places.