Complex sentence: Since the 1970s, he has lived in the hill station of Mussoorie in the Lower Western Himalaya; the surrounding region, especially the Garhwal Hills has provided much of the material for his writings.
Split into simpler sentences: Since the 1970s, he has lived in the hill station of Mussoorie in the Lower Western Himalaya. The surrounding region, especially the Garhwal Hills, has provided much of the material for his writings.