We are at DEFCON 3 because of the escalating tensions and military conflict between India and Pakistan, which has significantly increased the risk of nuclear engagement. This state of heightened alert, known as DEFCON Yellow or DEFCON 3, reflects a condition of increased readiness in response to the volatile situation, though it does not mean that nuclear war is imminent. The key reasons for moving to DEFCON 3 include the lack of clear de-escalation, unprecedented military activities including drone and missile strikes, and signs of nuclear posturing by both sides, raising the overall nuclear risk beyond normal levels.
DEFCON 3 signals a heightened state of military readiness where forces are prepared for possible rapid deployment, but it is not a declaration of war. Historically, DEFCON 3 has been used during other periods of heightened tension such as the Yom Kippur War, Operation Paul Bunyan, and the September 11 attacks.
In summary, the current DEFCON 3 status is a precaution driven by the ongoing India-Pakistan crisis and its potential implications for nuclear conflict risk.