Nixon faced several domestic challenges during his presidency including stagflation, an economic condition where inflation and unemployment rise simultaneously. Inflation reached 8% and unemployment rose to 7.5%, due partly to increased spending during the Johnson administration and on the Vietnam War. Nixon implemented a 90-day wage and price freeze in 1971 to address inflation. The 1973 OPEC oil embargo further exacerbated economic issues by restricting oil imports and increasing gas prices. Nixon responded with policies like the Emergency Highway Conservation Act and investing in nuclear power to reduce dependence on foreign oil. He also oversaw the creation of the Environmental Protection Agency and passage of environmental laws such as the Clean Air Act.