Three criteria for Melakarta ragas in Carnatic Music

In Carnatic music, rāgas are classified as Janaka rāgas and Janya rāgas. Janaka rāgas are the rāgas from which the Janya rāgas are created. Janaka rāgas are organised as Melakarta rāgas. A Melakarta rāga is one which has all seven notes in both the ārōhanam (ascending scale) and avarōhanam (descending scale). The 72 melakarta ragas are split into 12 groups called chakras, each containing 6 ragas.

Ragas must contain the following characteristics to be considered Melakarta.

• They are sampurna ragas - they contain all seven swaras (notes) of the octave in both ascending and descending scale
• They are krama sampurna ragas – that is the sequence is strictly ascending and descending in the scales, without any jumps or zig-zag notes
• The ascending and descending scales must have the same notes

Source: Wikipedia