The South Western Ghats montane rain forests are an ecoregion of southern India, covering the southern portion of the Western Ghats range in Karnataka, Kerala and Tamil Nadu, at elevations over 1000 meters. They are cooler and wetter than the lower-elevation South Western Ghats moist deciduous forests, which surround the montane rain forests.
The South Western Ghats montane rain forests are at elevations over half a mile.
The context states that the South Western Ghats montane rain forests are at elevations over 1000 meters, which is more than half a mile. I think that the system found this difficult because the units of measurements were different.