Official guidelines censor films that "promote cults or superstition." And dead returning as ghosts would seem to count, even when couched in the scientific terminology of the movie. No matter how many proton packs, it's still ghoulies from beyond…
Which does bring up another matter. What about Marvel's Doctor Strange? The film has cast Benedict Cumberbatch, a huge star in China courtesy of Sherlock. The movie has also been de-Tibetanised with Chinese sensitivities in mind. But it stars a Sorceror Supreme. Whichever way you slice it, that's "superstition"….
It's what led to Noah, Crimson Peak and Ben Hur being deprived of a release, of Pirates Of The Caribbean: Dead Man's Chest – though World's End got through with heavy cuts.
And Doctor Strange? Well-connected sources tell me that the filmmakers have been very aware of sensitivities during production.
The usual trick is to introduce an element that suggest magic is an illusion, a hallucination, a trick of the mind…. could that happen here?