This year's much-reduced crowd gathered on the city's Belgrave Road, also known as the Golden Mile, to see it illuminated with lights and colour.
The festivities have taken place after it was cancelled last year due to the Covid-19 restrictions.
The lights along Leicester's Golden Mile are usually turned on two weeks before Diwali day - which is on Thursday November 4 this year - with the festivities believed to be the largest outside of India.
ITV News Correspondent Rajiv Popat reports from Belgrave Road just before the Diwali lights switch-on in Leicester
This year, Leicester City Council urged attendees to take a lateral flow test before heading out to the festivities, and asked people to stay at home if they tested positive or felt unwell.
The city council said measures have been put in place to discourage too many people from gathering in one place at the same time.
Diwali (the festival of lights) is often celebrated by millions of Hindus, Sikhs and Jains around the world.
Celebrating the festival usually involves decorating the home - including painting colourful designs (rangoli patterns), visiting the temple, prayer, feasting and gathering with family and friends.
Social-distancing and crowd control measures have been put in place this year to keep people safe, Leicester City Council said.
The Deputy City Mayor of Leicester, Councillor Piara Singh-Clair, told ITV Central: "This year we have a one-hour recorded programme and three different giant screens.
"There is also a Diwali mela and there will be food and drink stalls as well as a fire garden," he added.
The screens showed a pre-recorded cultural programme and countdown, and the fire garden was also set up in Cossington Park, just off Belgrave Road, in the place of fireworks.