Democratic presidential frontrunner Joe Biden once again said he would ban the production of oil and natural gas on public lands if elected during a debate in Washington, D.C. on Sunday night.

While Biden has been criticized by environmental activist groups for not having a bold enough plan on energy and climate, prohibiting production on federal lands has been a constant in his policy platform. His campaign website calls for “banning new oil and gas permitting on public lands and waters.”

In the debate, Biden listed of a number of proposals aimed at the oil and natural gas industry.

“Number one, no more subsidies for the fossil fuel industry, no more drilling on federal lands, no more drilling, including offshore, no ability for the oil industry to continue to drill, period, ends, number one,” Biden said.

He then said, “No more — no new fracking.”

Biden’s statement immediately drew questions about if he was outlining new policies that would make all oil and natural gas production illegal, but his campaign quickly clarified his position hadn’t shifted.

Axios reporter Ben Geman tweeted that the “campaign confirms to me that Biden was ‘restating his policy as it relates to public lands.’ Reminder that his plan calls for ‘banning new oil and gas permitting on public lands and waters.’”

Since winning the South Carolina primary on Feb. 29, Biden has racked up a number of big wins across the country and has firmly established himself as the favorite for the Democratic presidential nomination.

His lone serious competitor left in the primary is Sen. Bernie Sanders (I-VT.), who has embraced aggressive climate and energy positions including support for the Green New Deal and a nationwide fracking ban and he has been endorsed by high-profile activist groups like the Sunrise Movement.

A study from the American Petroleum Institute published last month said that a nationwide fracking ban would cost the American economy $7.1 trillion in GDP by 2030 and that western states with substantial development on public lands would experience widespread job losses.

Western Wire has reported that political leaders across the west have expressed concerns about the energy policies of Biden and Sanders. U.S. Rep. Scott Tipton of Colorado and Wyoming Sens. John Barrasso and Mike Enzi are both adamantly opposed to banning development on public lands.

If Biden successfully secures the Democratic nomination, he will have a fine line to walk on energy and environment issues in the general election.

He will face the difficult task of bringing activist groups like the Sunrise Movement who are supporting Sanders over to his side, even has they continue work against his campaign in the primary. And he will need to assuage the concerns of organizations like who want him to take a firmer stance on climate change.

At the same time, Biden must avoid alienating the moderate voters who have powered his candidacy so far and the independent voters he’ll need in November. His campaign website expresses general support for the Green New Deal and last year he said, “I guarantee you, I guarantee you we’re going to end fossil fuel and I am not going to cooperate with them. Before 2050, God willing.”

A union worker in southeast Ohio, part of the high-producing Marcellus Shale, said it would be “political suicide” for a presidential candidate to come to the region and say they’re against oil and natural gas development, Bloomberg News reported.