Central Board of Indirect Taxes and Customs (CBIC) has urged businesses to file on time various tax return forms falling due in the next few days as part of an online campaign to encourage compliance.CBIC wants businesses to file GSTR-1 form, relating to sales made in April, which falls due on Wednesday, to be filed on time. This form is an important part of the reporting framework in GST, given that tax credit is passed on to buyers of goods and services based on the supplies made by sellers which are to be reported in GSTR-1. CBIC said that late filing of this return will result in late fee liability. The May 11 due date applies to those businesses which have not opted for a quarterly return filing facility.