Like most westerners discovering Hindi films and music, I fell in love quickly with the wonderful song form known as “qawwali.” People have many different interpretations on what a true qawwali is; I am just going to list my favorite film qawwalis, which I know have taken some liberties with the pure form. I like this particular article about qawwali and its history and development.
My personal criteria are that there be at least one singer with a chorus, and the song should build in rhythm, accompanied by clapping in addition to musical instruments and picturized in front of an audience which joins in. I also prefer the ones from older films which use more traditional instruments (e.g. dhola, harmonium, tabla, sarangi), and which usually begin with an alaap. If a “nautch-girl” is dancing, I consider that a mujra, not a qawwali. My definition and preferences might be too narrow for some, and too broad for some, but hey—it’s my blog!