Dhai is a yoghurt made in the Himalayas from Yak or Chauri milk.
The milk is boiled, then cooled to about 99 F (37 C.) A small amount of Dhai from the previous batch is added to act as a starter. The mixture is then allowed to set and ferment overnight.
Dhai can be used for making cheeses such as Serkam from (see entry on Yak Cheese.)
Called “Dahi” in India.