Diwali has been celebrated with music, dancing and live performance in Trafalgar Square.
The five-day Festival of Lights is celebrated in India and around the world by Hindus, Sikhs and Jains.
It was the 11th year that the festival, which celebrates the victory of good over evil, was marked at the central London landmark.
The event was organised by the Mayor of London in association with the Diwali in London Committee.
Boris Johnson said celebrations such as Diwali added to London's "vibrant cultural calendar".
"It's a festival, which with values rooted in peace and mutual respect, is of relevance to all Londoners as well as to Hindus, Sikhs and Jains," he said.