California's San Joaquin Valley officially failed its 1997 clean air deadline
What happened
US environmental regulators are proposing to declare that California's San Joaquin Valley did not meet its 1997 ozone standard. This means the state must now implement tougher pollution controls for the region.
Why it matters
The air in California's San Joaquin Valley is still not clean enough. This formal finding means the state must now implement more aggressive plans to reduce ozone pollution. It can no longer delay stricter measures.
The signal
Watch for California to propose new, stricter pollution controls for the San Joaquin Valley, and how local industries respond.