A neti pot is used for nasal irrigation, which entails flushing out your nasal cavity with a saline solution. The benefits include improved sinus symptoms and decreased sinus medication use. The basic explanation of how the Neti pot works is that it thins mucus and helps flush it out of the nasal passages.
The Neti pot originally comes from the Ayurvedic/yoga medical tradition.
To know how to use a neti pot – https://www.wikihow.com/Use-a-Neti-Pot