Exit clearance requirement: non resident workers must secure employer undertakings or certificates ensuring tax liabilities are covered before departure. Clause 420 requires non domiciled persons who came to India for business, profession or employment and derive income from India to obtain a no objection certificate based on a prescribed undertaking from their employer or payer before leaving; persons domiciled in India must furnish PAN, travel purpose and estimated period or a prescribed certificate, and authorities may require certification of no liability with safeguards and recovery provisions including owner or charterer liability as assessee in default.