Vandertop, a co-founder of Don't Mess with the Don, says the restaurant chain Tim Hortons has a big problem when it comes to litter. The registered charity, run by volunteers, cleans up trash from ravines in the Don Valley and says it has picked up about 136,078 kilograms of garbage in the past six years.

The number one brand it finds in its garbage cleanups is Tim Hortons, Vandertop said.

"Imagine — Tim Hortons has more than 4,000 stores across Canada now and that would be millions and millions of cups and lids all strewn out throughout our parks, streets, wild spaces. And this is only cups and lids. There's also food wrappers, containers and other beverage containers," she said.

"I think Tim Hortons, as a flagship Canadian company, has a tremendous opportunity here to do something good for the world and for the environment that we live in. This is not in line with the times."

Karen Wirsig, senior program manager for plastics at Environmental Defence, an environmental advocacy organization, said it's important to hold corporations accountable for the waste they produce. Wirsig said Tim Hortons is a major generator of single-use plastic waste when it comes to its takeout packaging.