Shaykh Ibn Uthaymeen was asked:

Question:

The Prophet (ﷺ) said:

إذا توضأ أحدكم فليجعل في أنفه ماءً

If anyone of you makes wudu, then let him put water in his nose

[Saheeh Muslim no. 237]

Some people have allergies in their noses or other than it and are not capable of snuffing water into the nose. So what does [such a person] do?

Answer:

“It is not necessary to snuff water. That is: if he takes water in his hand until he enters it to the nostrils, that suffices. The water reaching the top of the nose is not an obligation and I do not think, inshallah, that there is any harm in it”

[Liqaa al-Bab al-Maftooh no. 215]

Translated by

Faisal bin Abdul Qaadir bin Hassan
Abu Sulaymaan