The US is hoping that ports in Canada and Mexico could help it to export coal to Asia, to get around the blocking of shipments by some US coastal states.

California, Washington and Oregon are reported to have “blocked permits for coal ports” on concerns about coal's impact on climate change.

US Energy Secretary Dan Brouillette said on Friday that such exports could be facilitated by the new North American trade agreement, the United States-Mexico-Canada Agreement (USMCA), Reuters reported.