Why was this question ("Historically, when (and why) did Ganga become a holy river? Is it after Sarasvati dried up?") migrated to History.SE? For those who can't see the deleted/migrated post, check the same question on History SE.
It was asked in 2014 and remained on-topic for 4 years before being migrated. How did it suddenly become off-topic in May, 2018? I don't remember seeing any discussion on meta regarding this. Did one of the mods of this site unilaterally decide to migrate it with no input from the community?
There were several close reviews and all of them ended with leaving the question open.
The last comment under the question was this:
Are you looking from story from Purana / Hinduism point of view or historical? – Pandya♦ May 8 '18 at 7:21
From the timeline and current status of the question:
This question was migrated to History Stack Exchange because it can be answered by historians and history buffs. Migrated 2 years ago by JNat♦.
Post Migrated Away to history.stackexchange.com by JNat♦ occurred May 14 '18 at 9:37
Post Closed as "Not suitable for this site" by JNat♦ occurred May 14 '18 at 9:37
We have several other questions of this type which were accepted here (see examples below) and not migrated to History SE so why was only this question migrated? Was the question making some users uncomfortable due to its historical nature and is that the main reason it was migrated?
Are there any strong evidence that Hinduism religion is an ancient one?
How has Lord Vishnu's understanding developed and what was his role initially?
Aryan Migration theory—evidence for and against it in the Vedas