Revocation of cancelled GST registration allowed after outstanding returns filed and intervening returns submitted within thirty days. Where registration is cancelled from the date of the cancellation order, all returns due up to that cancellation date must be filed before seeking revocation, and returns for the period from cancellation to revocation must be filed within thirty days of the revocation order. For retrospective cancellations where the portal blocks return filing, a proviso allows filing of a revocation application provided all returns for the period from the effective cancellation date to the revocation date are furnished within thirty days of the revocation order.