By Jon Hurdle, NPR State Impact.

Thousands of campaigners for clean energy marched through the center of Philadelphia on the eve of the Democratic National Convention on Sunday, urging the party to adopt policies that would ban fracking and promote the use of renewable energy.

In an event that mixed national politics with local opposition to specific energy projects, some demonstrators called on the Democratic presidential nominee, Hillary Clinton, to step up her support for renewable energy, while others – many of them backers of Clinton’s former rival, Senator Bernie Sanders — vowed never to support Clinton even if that increased the chances of the Republican nominee, Donald Trump, becoming president.

Carrying signs such as “NeverHillary – Bernie or Bust” and “Fracking is Not a Bridge – Are You Listening Hillary?” demonstrators marched from City Hall down Market Street to Independence Mall on a sweltering day, in a peaceful but noisy event that called on state and national authorities to ban fracking and associated activities including pipelines and oil trains.