The black rain in Tehran was created by the mixing of toxic smoke from burning oil facilities with rain clouds after US and Israeli airstrikes on Iranian oil facilities[1][2]. This phenomenon represents a mixture of different types of pollution, the main component of which is black soot particles formed during the combustion of hydrocarbons without sufficient air access[1][3]. Residents of Tehran have reported symptoms such as burning eyes, difficulty breathing, and greasy stains on surfaces after the fall of this polluted rain[1][3]. The World Health Organization and Iranian authorities have warned that polluted rain can contain harmful hydrocarbons, sulfates and nitrates, as well as microscopic soot particles that can penetrate deep into the lungs and enter the bloodstream[1]. These pollutants not only cause immediate respiratory and ocular irritation, but may pose long-term health risks, including an increased risk of cancer[1]. Health authorities advised residents to stay indoors, wear masks and avoid contact with contaminated water[1][2].