Complex sentence: The Juárez cartel has been found to operate in 21 Mexican states and its principal bases are Culiacán, Monterrey, Ciudad Juárez, Ojinaga, Mexico City, Guadalajara, Cuernavaca and Cancún.
Split into simpler sentences: The Juárez cartel has been found to operate in 21 Mexican states. It's principal bases are Culiacán, Monterrey, Ciudad Juárez, Ojinaga, Mexico City, Guadalajara, Cuernavaca and Cancún.