SACRAMENTO — California denied 21 oil drilling permits this week in the latest move toward ending fracking in a state that makes millions from the petroleum industry but is seeing widespread drought and more dangerous fire seasons linked to climate change. State Oil and Gas Supervisor Uduak-Joe Ntuk sent letters Thursday to Aera Energy denying permits to drill using hydraulic fracturing in two Kern County oil fields to protect “public health and safety and environmental quality, including [the] reduction and mitigation of greenhouse gas emissions.” Aera Energy, a joint venture of Shell and ExxonMobil, called the permit denials “disappointing though not surprising.”