Named Happy Street, the permanent installation is located on Thessaly Road – a key route between Wandsworth Road and Nine Elms Lane that was previously a "forbidding environment".
The installation, which forms part of the local council's ongoing initiative to make the area more welcoming, was developed by Ilori in collaboration with input from the local people and primary school.
Happy Street, Illori's first installation in a public realm, comprises 56 patterned-enamel panels decorated with 16 different colours, chosen for their low-cost and durability.
"I am really honoured and blessed to have my first public realm project installed in Nine Elms, Battersea," said Ilori. "The most important part of the project was talking to the community, especially the young children and seeing the smiles on their faces when they walk under the bridge has been magical."
"I just hope this bridge continues to bring happiness to everyone who walks under Happy Street and inspires the next generation of young artists because they are the future," he added.
His use of bright colours across the installation is intended to echo the Thames sunsets, in a bid to encourage passersby to encourage them to become more aware of their surroundings.
At night the underpass is illuminated to provide passersby with an "increased sense of safety".
"I am delighted that this Nine Elms rail bridge has been so successfully transformed into a colourful gateway," added Ravi Govindia of Wandsworth Council. "Together with Yinka Ilori we listened to community concerns and worked closely with local residents and St George's school to ensure we delivered a design that they would be happy living next to."
"I hope that what we see here gives fresh inspiration to reimagine London's built environment and consider incorporating art into other structures around us," he added.
Yinka Ilori is a London-based artist and designer, and a Dezeen Awards judge for 2019.
He also recently completed The Colour Palace at Dulwich Picture Gallery in collaboration with architecture studio Pricegore, which is modelled on traditional African textiles, an installation for Pinterest in Cannes and a show at Somerset House celebrating 50 years of black creativity.
Photography is by Luke O'Donovan.
Designer: Yinka Ilori
Architectural support: Red Deer Architects
Client: Wandsworth Council/London Festival of Architecture
Site owner: Network Rail
Structural engineer: Project Centre
Contractors: Space Making/FM Conway/Wandsworth Operational Services