Geographically , Gili Iyang is located on the east of Madura Island, at Sapudi Strait. It takes about 15 minutes or 2.41 miles from Dungkek Port by boat. Gili Iyang is 9.15 kilometes square.
Lately this island become topics as according to Balai Besar Teknis Kesehatan Lingkungan dan Pengendalian Penyakit (Technical Center for Environmental Health and Disease Control) of East Java, this island has 21.5% oxygen level, more than the average level: 20% by taking samples of sea water, fish, air and 20 local who are older than 80 years. Even found local which is older tahn 175 years.
The oxygen level 21.5%, CO2 265ppm from the threshold 387 and noise level 36.5 db. This means the oxygen is above the normal quality which is very good for health. From that fact, people call this island as Island of Forever Young.
This special feature of this island was found out in 2006, when researchers of National Institute of Aeronautics and Space (LAPAN) discovered this from the monitoring of satellite that the oxygen level in this island was high. LAPAN then undertook a 3 months research by situating 8 oxygen measuring instrument in its air. The result is that C)2, CO, NO2, and SO2 in this island is much lower than the threshold. This was measured from transition of dry season to wet season. When rainy season season shift to dry season, the oxygen level is higher.
This high O2 level was caused by the air velocity of the sea around the island. The Island is barely unpolluted.
One factor which caused this is also the existence of caves in this island, according to record there are 17 caves.