It’s not recommended in US but apparently it’s big in Thailand, some 80% of the population making use of it as a part of traditional medicine (Hatha Yoga) - Thailand was famously doing very well for the first year (low case rates), but apparently they have since caught up.

One article with lots of interesting stats (get your Adblock ready): https://www.indiatoday.in/news-analysis/story/did-nasal-rins...

General details on the practice: https://en.m.wikipedia.org/wiki/Neti_(Hatha_Yoga)

Usually it is not recommended due to the risk of https://en.wikipedia.org/wiki/Naegleria_fowleri

Thanks, I vaguely remembered some bad news about it but did not imagine it was brain eating amoeba ! Apparently all that’s needed to avoid this is using sterile saline solution or first boiling the water, but I don’t know whether the ol’ sacred texts include this bit of advice.