Dr Phoolan Prasad has done significant work in the area on non-linear hyperbolic equations. He has succeeded in assessing the basic properties of the equations of various physical phenomena, generalized these mathematical properties and then used his theory to explain new results in the field of non-linear waves. He has given the proof of the existence of a new type of wave on the interface of a clear liquid and a mixture in a sedimentation process; this has been confirmed by recent experiments.