Bilawal is a raga and basic "thaat" (musical mode) in Hindustani classical music, it is equivalent to which rāga in Carnatic music?
Bilaval:  It is equivalent to the Carnatic melakarta raga Dheerasankarabharanam, as well as the Western Ionian mode (major scale) and contains the notes S R G m P D N S' ("see swara for explanation"). Dheerasankarabharanam: Dhīraśankarābharaṇaṃ, commonly known as "Śankarābharaṇaṃ", is a rāga in Carnatic music.
i don't know