One of the world's biggest drug lords, Ismael "El Mayo" Zambada, leader of Mexico's Sinaloa cartel, has been arrested by US federal agents in El Paso, Texas. Zambada, 76, founded the criminal organisation with Joaquin "El Chapo" Guzman, who is currently jailed in the US. Arrested with Zambada on Thursday was Guzman's son, Joaquin Guzman Lopez, said the US justice department. In February, Zambada was charged by US prosecutors with a conspiracy to make and distribute fentanyl, a drug more powerful than heroin that has been blamed for the US opioid crisis. In a written statement on Thursday evening, US...