Texas Governor Greg Abbott has sent a letter to US President Joe Biden expressing his opposition to the possibility of tightening ozone emissions regulations in part of the Permian basin — a move that could cut oil and gas production in the nation’s most prolific play.

The US Environmental Protection Agency (EPA) in June announced that it was considering tightening air quality requirements in undisclosed areas of the Permian shale in both New Mexico and Texas. The agency cited high levels of methane emissions being an issue of concern.