The White House will enact greenhouse gas emission rules for power plants in the “not-too-distant future,” Heather Zichal, President Obama’s top climate adviser, said Monday.

The proposed Environmental Protection Agency (EPA) standards for coal-fired power plants are “pretty historic” and “very much in line with the president’s broader climate objectives,” Zichal said at a Washington, D.C.-area conference hosted by Transportation Energy Partners.

Zichal made the comments after a recent Washington Post report suggested the administration might postpone and tweak the emissions rules, which were proposed about one year ago over strong opposition from industry groups and congressional Republicans.