News of black rain falling on Tehran felt all too familiar to Nejat Rahmanian as he scrolled through alerts on social media feeds and tried to contact relatives on March 8. Israeli drone strikes hit giant oil depots and refineries on the outskirts of the Iranian capital a few hours earlier, setting fuel on fire and releasing columns of black smoke, which mixed with rain clouds that poured toxic chemicals onto the city later in the day. The descriptions reminded the Iranian researcher of a...