Ganja is a slang term for cannabis and the word is associated with the West Indies, but actually originated in India.
Merriam-Webster Online Dictionary
ganja (noun) a potent and selected preparation of marijuana used especially for smoking , broadly - marijuana
Cannabis, Mary Jane, Ganja, Dope, Reefer, Hash, Bud, Chronic, Skunk, Green, Smoke, Joint, Blunt, Doobie, Spliff, Kush, Hemp, Sativa, Indica
