Complex sentence: Their population of 4,200 is centered in West Kameng onto the villages of Rupa, Jigaon, Thongri, Shergaon and Doimara, in Bomdila, all of these are at elevations between 5000-6000 feet above sea level.
Split into simpler sentences: Their population of 4,200 is centered in West Kameng in the villages of Rupa, Jigaon, Thongri, Shergaon and Doimara, in Bomdila. All of these are at elevations between 5000-6000 feet above sea level.