Indian classical is different from Western Classical in that there is no concept of written notes that govern a recital. A raga, which is the basic framework for a performance, provides a skeleton. The performer is then at complete freedom to stretch it's definition per his/her imagination.
From Wiki: A raga uses a series of five or more musical notes upon which a melody is constructed. However, it is important to remember that the way the notes are approached and rendered in musical phrases and the mood they convey are more important in defining a raga than the notes themselves. In the Indian musical tradition, rāgas are associated with different times of the day, or with seasons. Indian classical music is always set in a rāga. Non-classical music such as popular Indian film songs and ghazals sometimes use rāgas in their compositions.
In this rendition, you can see how some notes have been stretched on for minutes on end, that it's almost like a jam session!
This raga is an evening raga, meaning it was meant to capture the mood of people in the evenings. Men coming home after a day of labour in the fields; women after slogging in the house all day - could both relax to this music. I'm not sure if beer was common in those days ;-), but Indians have always loved their wine!