Urgent : necessity of permanent establishment for exhibition

Dear friends

One of my clients has made foreign remittance for participation in exhibition of  US$1,388 to Dubai World Trade Centre LLC & therefore hasn't deducted TDS. In this case, is this necessary that  Dubai World Trade Centre LLC should not have any permanent establishment in India before signing Form No. 15CB  by the CA.???

Regards

CA ROOPA CHHABRA