https://ums.org/2014/03/03/qawwali-more-familiar-than-you-think/
What is qawwali instrument?
Traditional qawwali instruments are harmonium, sarangi, tabla, and dholak. Clapping, an important percussive component in qawwali music, serves as a rhythmic drone and is sustained throughout a song. Instruments like congos, khartal, and morsing are sometimes added by regional qawwali ensembles.