At times, the rally had the boisterous feel of a rock concert.

"How's it going, Philadelphia?" Josh Fox, movement celebrity and maker of the film Gasland, yelled into the microphone as the crowd cheered.

As more than two dozen police officers lined Arch Street and coat-and-tie participants at a two-day Marcellus Shale industry conference looked down from Convention Center windows, hundreds of activists held a two-hour anti-fracking rally Wednesday.

"We're going to show this industry how strong we are and how unacceptable gas drilling is," said West Philadelphia resident Iris Marie Bloom, founder of the nonprofit, Protecting Our Waters, and rally organizer. She told the crowd that "we are 65 organizations strong. You look beautiful."

They cheered again, chanted slogans like "no fracking way" and waved signs that read, "Pass Gas, Go Renewable." and "Don't Frack Mother Earth."

Much of the anger and the comments were directed at the Delaware River Basin Commission, which has scheduled a special two-hour meeting on Oct. 21 to consider the adoption of regulations that would allow natural gas drilling to go forward.

Some northeastern Pennsylvania counties underlain by the Marcellus Shale are in the basin, and drilling there has been halted until the commission adopts rules. The basin provides drinking water for more than 15 million people, including Philadelphia and some of its suburbs.

At one point during his speech, Fox, took out his cellphone and dialed the number of the commission, urging the crowd to do likewise. "Let's call them and tell them what we think," he said, later adding with a shrug, "It's busy."

"Tell them you are showing up on Oct. 21," he said. "We are not going to let this happen." At one point, he said he was prepared to go to jail to fight drilling in the basin.

The former commissioner of the New York City Department of Environmental Protection, Al Appleton, said the basin fight was crucial. "However much we want to say 'ban the whole thing,' we must first ban it in the Delaware River Basin," he said. "This is actually a battle for the future . . . the future is green energy."

Apparently, participants were getting reports on what was happening inside the conference. Not long after word arrived of Chesapeake Energy CEO Aubrey K. McClendon's luncheon address, during which he downplayed the incidence of contaminated wells and accidents, New York City activist David Braun chided, "Aubrey, correction, we have people here today who were hurt."

Craig and Julie Sautner of Dimock also mounted the stage later at the rally. "This Sunday will be three years of putting up" with a contaminated well, he said. "When is enough?"

Earlier in the day, people who described themselves as victims of natural gas drilling spoke at a news conference. They included Janet McIntyre of Butler County who said her well water became contaminated after drilling started near her home, and "our once fresh air is sour air."

Some participants had arrived from Harrisburg, New York and elsewhere by the busload. Paula Paul of Philadelphia was part of the group, the Granny Peace Brigade, aiming to help keep the event peaceful. At 70 years old, she said, she only had so much time to leave things right for future generations.

City Council member Blondell Reynolds Brown urged the crowd to "keep up the fight."

Doug Shields, president of Pittsburgh's city council, which banned fracking within the city limits, called natural gas drilling "one of the most important issues of our time." He said the industry "will leave us all with a legacy of woe and want. They're going to walk away from this with trillions of dollars, while we pay through the nose."

Toward the end of the rally - before a march passed the regional office of the U.S. Environmental Protection Agency, President Obama's reelection office and Gov. Corbett's Philadelphia office - participants passed buckets to take up a collection for further efforts.

"Dig deep. Help us out," said Braun. "We don't have the money that the industry has."