What evidence would indicate that Ukraine’s air defenses are depleted?

Signs that Ukraine’s air defenses are running low are visible in the data. The number of successful Russian aerial strikes on targets that were once protected has gone up. In high-threat zones, there is a sustained lack of radar activity or missile firings. Reports confirm that air defense assets have been destroyed, disabled, or left unreplenished. Enemy tactics have shifted too, with unchallenged low-altitude flights and saturation attacks suggesting a drop in defensive capability. These indicators are observable, loggable, and quantifiable, matching established facts.