The Assamese are a mixture of Mongolian-Tibetan, Aryan, and Burman ethnic origins. Their language is akin to Bengali, spoken in West Bengal and in Bangladesh. Since the late 19th century a vast number of immigrants from Bangladesh have entered the valley, where they have settled to cultivate the almost empty lands, particularly the low floodplains. The hilly margins of the plain are inhabited by the hill tribes of the Garo, Khasi, and Hajong. The Bodo are the largest minority group in Assam and are concentrated in the northern areas of the Brahmaputra River valley.
Agriculture is basic to Assam's economy.
Oil and coal are found in upper Assam, and the state produces about one-sixth of India's petroleum and natural gas. The Eri, Muga and Pat are the important silk products of Assam. Assam has mild winters and warm summers. Summer is March to June and monsoon from July to August. November to February is winter.