With weeks to go before the launch of a plan to toll drivers in Manhattan’s core commercial district, advocates and organizers of congestion pricing had been celebrating a victory years in the making.

They were shellshocked on Wednesday and furious with Gov. Kathy Hochul after she indefinitely suspended the plan, saying she didn’t think the time was right for a tolling scheme that could deter visitors to Manhattan and slow the city’s economic recovery from the pandemic.

Those who had fought for congestion pricing had been eagerly awaiting the implementation of an idea conceived here 72 years ago — one that aimed to transform the city’s busiest streets and set an example for other American cities that are battling traffic and pollution.

But they woke up to devastating news on Wednesday, when it was revealed that Ms. Hochul had been quietly working to postpone the program. Advocates said they were crestfallen.

“We’ve been blindsided,” said Kate Slevin, executive vice president of the Regional Plan Association, an urban planning nonprofit in New York. “It’s a betrayal of millions of transit riders and the future of New York’s climate and economy.”

Upon hearing about a possible delay, the Riders Alliance, a grass-roots organization of transit riders, assembled a protest in front of Ms. Hochul’s New York offices. Their anger grew following her announcement.