Screens with images and information about bonded labour joined advertisements for Labour Day sales in at least four popular malls in Karnataka's Bengaluru.
Shoppers were encouraged to snap selfies in front of the digital displays and post them to social media in order to raise awareness of the crime, so they would be more likely to recognise and report it.
"Lack of awareness is a hurdle in effectively combating the crime," said Jagadish Kempalakkegowda, a state government official who spoke about the issue on three popular radio stations on Tuesday.
"We have released more than 100 people from bondage in the last eight months from around the city, and are appealing to citizens to complain if they spot such cases," he told the Thomson Reuters Foundation.
Banned in 1976, bonded labour remains widespread across India, with tens of thousands of women, children and men trapped in a cycle of debt.
Most are duped into working without wages to pay off loans or inherited debts. But there is often no documentation of how much debt has been incurred or cleared, say activists, and the cycle can continue for months or even years.
Campaigners like the End Bonded Labour Coalition, which organised the mall displays, are trying to let the public know that the crime continues to this day.
"Most think bonded labour does not exist anymore, but it does and most of us don't recognise it," said Nupur Singh a marketing manager at the Mantri Square mall, which sees an average of more than 1 million visitors every month.
"They don't stop to think about the child selling them roses at the traffic lights," she said by telephone. "We wanted them to pause and think as part of the campaign."
Singh said Tuesday was the perfect chance to raise awareness.
"A lot of people came to malls because it was a holiday and we wanted them to know why LabourDay was important," she said.
Get Breaking news, live coverage, and Latest News from India and around the world on NDTV.com. Catch all the Live TV action on NDTV 24x7 and NDTV India. Like us on Facebook or follow us on Twitter and Instagram for latest news and live news updates.