PSF and UDF chargedby airport operators are consideration for providing services to passengers. Thus, services provided by an airport operator to passengers against consideration in the form of UDF and PSF are liable to GST.PSF and UDF being charges levied by airport operator for services provided to passengers, are collected by the airlines as an agent and is not a consideration for any service provided by the airlines. Thus,airline is not responsible for payment of ST/GST on UDF or PSF. The airport operators shall pay GST on the PSF and UDF collected by them from the passengers through the airlines.The collection charges paid by airport operator to airlines are a consideration for the services provided by the airlines to the airport operator (AAI, DAIL, MAIL etc) and airlines shall be liable to pay GST on the same under forward charge.

Link