All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
The delayed dowry is a debt which the husband is obliged to pay, and a debtor is obliged to pay whatever debts he owes. Therefore, you have the choice either to pay in Pakistani currency (i.e. 50,000 Rupees) or using another currency, provided that this will be at the exchange rate of the same day when you pay the dowry.
Ibn 'Umar narrated that he came to the Prophet and said to him: ''I sell camels in Al-Baqee', for Deenaars (golden currency) and take Dirhams (silver currency) for them, and sell for Dirhams and take Deenaars for them." Thereupon, the Prophet said: ''There is no harm in this provided you take the amount at the current rate of the same day and so long as you do not separate leaving something to be settled." [Ahmad].
For more benefit, please refer to Fataawa 83231 and 83166.
Allaah Knows best.