In 2016, the Bureau of Land Management (BLM) issued a rule requiring oil and gas operators to capture a certain percentage of natural gas (which is mostly methane) produced on federal and tribal lands (the Obama Methane Rule).  Industry groups and several states challenged the Obama Methane Rule in a suit filed in Wyoming.
In 2018, BLM replaced the Obama Methane Rule with a new rule (the Trump Methane Rule).  The State of California challenged the Trump Methane Rule in a suit filed in California.  As the two suits proceeded, those challenging the Obama Methane Rule asked the Wyoming court to stay the case, pending the outcome of the California case.

California Decision Restarts Wyoming Case
Earlier this month, the California court vacated the Trump Methane Rule and reinstated the Obama Methane Rule.  However, acknowledging the existence of the Wyoming case, the California court stayed the effect of its ruling for 90 days, to allow the Wyoming court to rule on the challenge to the Obama Methane Rule.

Less than a week after the California court’s ruling, the Wyoming court lifted its stay and required final briefs filed by September 4, 2020.

Lengthy Process of Rulemaking and Court Review of the Rules
Both cases are in district (trial level) courts.  Finality is unlikely until the Courts of Appeals issue their rulings of appeals from the district court decisions.  If both rules are vacated, operators and regulators will need to determine what rule was in place before the Obama Methane Rule.

It is not easy for administrative agencies to issue rules that can survive court challenges.  Changing existing rules is often even more challenging.  Our federal regulatory system resists rapid change.