Pancham or panchama is the fifth svara from the seven svaras of Hindustani music and Carnatic music.
[1][2] Pancham is the long form of the syllable प.
[3] For simplicity in pronouncing while singing the syllable, Pancham is pronounced as Pa (notation - P).
Regarding panchama and its importance in Indian classical music: So the svara Pa is formed from Shadja.
Consequently, the Pa after the Ma of 640 Hz (Taar Saptak) has a frequency of 720 Hz i.e. the double of the Lower octave Pa. For example, if these are the 4 Shruti's of Pa then, Pa (svara)