Duty to realise foreign exchange requires prompt repatriation and forbids actions that delay or cause cessation of receipt. A person resident in India to whom foreign exchange is due or has accrued must take all reasonable steps to realise and repatriate that foreign exchange to India, except as provided by the Act, rules or with authorised permission; and must not act or omit to act so as to delay receipt or cause the foreign exchange to cease to be receivable.