Transitional Input Tax Credit requirement: file FORM GST TRAN-1 to declare pre GST VAT or service tax paid and claim ITC. Persons covered by clause (c) of sub section (11) of section 142 must electronically submit a declaration in FORM GST TRAN-1 within the prescribed period, furnishing the proportion of supplies on which VAT or service tax was paid before the appointed day but supplied after the appointed day, and stating the ITC admissible; States may prescribe the methodology for calculating VAT eligible as State Tax ITC.