Industry chamber CII said on Sunday that in view of certain pending issues, the deadline for filing Goods and Services Tax (GST) returns should be further extended by up to a couple of months. In view of the difficulties of online filing, CII suggested that the due dates for filing GSTR 1, GSTR 2 and GSTR 3 should be deferred for another month or two. This will stabilise the system the Confederation of Indian Industry (CII) said in a release.