Pure agent treatment: airlines may exclude airport levies from supply value if conditions met, airport liable for GST. PSF and UDF charged by airport operators are consideration for services to passengers and are taxable under GST; airport operators are liable to pay GST on these levies even when collected through airlines. Airlines may exclude such amounts from their supply value if they qualify as a pure agent under Rule 33 by separately indicating the charges and GST in invoices, but airlines cannot take ITC on GST payable on PSF/UDF. Collection charges paid to airlines are taxable to airlines and ITC is available to airport operators; passengers may claim ITC on the basis of the pure agent invoice.