The name is unrelated to "ganja" (cannabis) except for a shared word root of "ganj" (treasure). I don't know what the anime would be about but the title makes as much sense as "Harry Potter: Pot Master".
Yeah, from my knowledge of Hindi and a few other Indo-European languages I can't think of any other word with the ganj- root/sound either. Another example (probably still closer etymologically) would be Harry Potter and The Sorcerer's/Philosopher's Stoned.
Well, the article says the "ganj" root in "Ganjifa" is Persian. I didn't know the etymology of the word "ganja" before so I had to look it up:
"Ganja" seems to originate in Vedic Sanskrit but its exact etymology seems to be unclear. It might be related to Sumerian "ganzigunnu" or it might be related to "Ganga", the Sanskrit name for the Ganges river. It might also share an origin with the word "cannabis" via Indo-Germanic.
In other words: it's unsurprising you wouldn't find related words in Hindi given that neither of the two words originates in Hindi, although Hindi is generally believed to be a modern descendent of Sanskrit (via Hindustani). The more relevant language to look at would be Farsi (i.e. Persian). With regard to Hindi they're two unrelated loanwords, one of which is even a proper noun.
I believe the first of these I encountered, years and years ago, was a photoshopped cover reading “Harry’s a Pothead and the Sorcerer’s Stoned”. Can’t pass up either near-reference to weed with so few words to work with.
It appears there are some full parody books under similar, but worse titles.
If you haven't seen it, there's Chihayafuru [0] which is an anime with the japanese card game, karuta (which comes from the portuguese "carta" for "card").
To be fair, thinking that would be completely fair for an English speaker being exposed to spoken Japanese, with how much more common homophones are in it compared to English.