TORONTO — The announcement was big enough for Prime Minister Justin Trudeau to fly down to Toronto and deliver. A corporate sibling of Google had been selected to transform a largely abandoned port area in Toronto into an innovative, sensor-laden, tech-centric city of tomorrow.

But almost from the time of its unveiling, the project — which combined environmentally advanced construction with a plan for sensors to track residents’ movements and actions — was hit by formidable opposition. Critics cast it as a recipe for a surveillance-driven, corporate-controlled urban dystopia and objected to turning over public spaces to one of the world’s wealthiest companies.

Now, nearly two and a half years later, the opponents have shown that even if you can’t fight city hall, you can take on Google and succeed.

After admitting that it had underestimated privacy worries with its original plan, the Google sibling, Sidewalk Labs, has retreated. A couple of weeks ago, it unveiled details of a much watered-down plan along with new privacy protections. But some critics remain unconvinced. Waterfront Toronto, a government agency, will announce in May if the project will proceed.