When a compass direction identifies where something is located, it commonly follows فِي.
الْبَحْرُ فِي غَرْبِ الْهِنْدِ
The sea is to the west of India.
- فِي is the preposition.
- غَرْبِ is majrur and mudaf.
- الْهِنْدِ is the mudaf ilayh.
New example:
الْمَكْتَبَةُ فِي شَرْقِ الْمَدِينَةِ
The library is in the east of the city.