With every new Genshin Impact update, we get new characters in the game, and to ascend them, we need to farm their ascension materials. One of them is the Sand Grease Pupa which is an ascension material required to ascend Alhaitham, and it will be available in Genshin Impact 3.4 update to farm.
As per the in-game description, "It is a hardened shell meant to protect the larval bodies of the Unagi until they finally acclimate to the conditions of the dry desert." As the description suggests, Sand Grease Pupa can be found in the Desert of Hadramaveth, and here are their exact locations for you to farm them quickly.
Genshin Impact: Sand Grease Pupa Farming Location
Sand Grease Pupa is a local specialty of the Desert of Hadramaveth and can be found deep (underground) in the desert where the Quicksand Eels breed. Here are the exact locations of Sand Grease Pupa in Genshin Impact marked on Genshin Impact Interactive World Map.
You will need a total of 168 Sand Grease Pupa to ascend Alhaitham to his highest level, and you can farm 74 of them in a single run. After that, you will have to wait for them to respawn to grab the next batch.
You can travel fast from one location to another by using Teleport Waypoints and the Statue of Seven to collect them quickly. In addition to this, make sure that your HP is enough to fight enemies, as you might encounter some while exploring.