If tax invoice could not be issued at the time of removal :
Where the goods being transported are for the purpose of supply to the recipient but the tax invoice could not be issued at the time of removal of goods for the purpose of supply, the supplier shall issue a tax invoice after delivery of goods – rule 7(4) of Invoice Rules.
In view of this rule, it can be argued that non-issue of tax invoice at the time of removal is not an offence.
If it is not possible to issue tax invoice, at least delivery challan should be issued.