Complex sentence: Sikkim, the only state in India with ethnic Nepalese majority, became part of India in 1975; other areas with significant Nepalese population includes Uttrakhand, Assam, Himachal Pradesh, Manipur and Meghalaya.
Split into simpler sentences: Sikkim, the only state in India with ethnic Nepali majority, became part of India in 1975. Other areas with significant Nepali population include Uttrakhand, Assam, Himachal Pradesh, Manipur and Meghalaya.