The subject of minorities is a very touchy one in any country, especially in nation-states where a national heritage or culture or identity (often dictated by the majority population) defines the characteristic of the state. Such modern concepts of states get complicated if there are other minorities that live in the state, each claiming to be a separate “nation” by virtue of its religion, language, culture, etc.
Bangladesh has about 12% religious minorities, including approximately 10% Hindus, the remainders being Buddhists, Christians, agnostics, atheists and animists. Roughly one percent of the population lives in the high hills, e.g., Jayintia, Garo Hills and Chittagong Hill Tract (CHT) districts. Historically the Bengal delta was husbanded by people who resorted to wet cultivation while the people in the hills, who were outside tax collection from ruling authorities, resorted to dry cultivation for their staple food. In the olden days of the Mughal rulers the authority of the state sometimes ended where the hills began. As we all know it was the marauding attacks from the Maghs (Arakanese Buddhists) and Portuguese pirates, which were sponsored by the Buddhist Kings of Arakan, that led to Shaista Khan’s campaign to re-conquest Chittagong and its hilly districts, ensuring these territories’ sovereignty within the Mughal rule. His campaign stopped shy of the present-day Arakan that demarcated itself from Bangladesh by the Naaf River. During the subsequent Nawabi rule of Bengal and British Raj the territorial boundary remained the same, i.e., both those districts remained integral to Bengal and outside Buddhist rules of Arakan, Burma and Tripura.
Unlike the Mughal and Muslim Sultanates of Bengal, the British Raj (esp. during the Company era) was more interested about collection of revenue and had little concern about the goodwill of the local people and their legitimate grievances whether or not such taxes were burdensome. It was their heavy handedness that led to the horrible famine of 1769-1773 (corresponding to Bangla Year 1176-1180, and more commonly therefore known as “Chiatturer monontor”) killing some 15 million people of Bengal (that included Bihar and Orissa). One in every three person perished in that great famine.
During the British Raj a more drastic and concerted effort was taken to reclaim hilly areas under taxation. In order to increase revenue collection, the Raj created local tribal chiefs in the Hilly districts, Rajas, who would ensure payment of such revenues. For the planes, it had by the 19th century already instituted a similar scheme of collecting revenues from the zamindars (not to be forgotten in this context the Sunset Law), who essentially became the enforcer of collecting such revenues in the form of money or kind (e.g., paddy) from the raiyats – peasants, and petty merchants. That is, the role of the zamindars was similar to a revenue collector in modern times.
The CHT districts with their deep forests, much like many other hilly parts of pre-modern era India, often became refuges to rebels and revenue- and tax-evaders who would settle (without its true connotation) there to escape from being hunted down by the ruling authority. In 1784 in the nearby Arakan there was a massive genocidal campaign that was steward-headed by the racist Buddhist king of Burma — Bodaw Paya — who had invaded the independent state. Arakan – the land of poets Alaol and Dawlat Kazi – had a significant population of Muslims (commonly known as the Rohingya people) who had lived in the other side of the Naaf River for centuries. [As shown elsewhere by this author, the origin of the Rohingya people of Arakan pre-dates the settlement of the Tibeto-Burman people there.]. The genocidal campaign by the Buddhist king led to a mass scale forced eviction and exodus of hundreds of thousands of people of Arakan to the nearby territories of British India, esp. to Chittagong and CHT districts of today’s Bangladesh. Nearly a hundred thousand people, mostly Muslims, were killed by the Burmese extermination campaign. The Mahamuni statue of Buddha itself was stolen away from the Arakan. Many Muslims were taken as slaves and forced to live elsewhere, e.g., in places like the Karen State of Burma.
Those Rohingya Muslims who were able to save themselves from Burmese annexation of Arakan, like many Magh Arakanese, settled mostly in the Chittagong and CHT districts. The Muslim refugees and their descendants that had lived and settled in those places came to be known by the local name Ruhis, depicting their Rohingya/Arakan origin. During the Anglo-Burmese War of 1824-26, Arakan and subsequently the vast territories of Burma came under the British Rule. The exiled Rohingya/Ruhi Muslims and Maghs of Arakan, and their descendants, were allowed and encouraged to resettle in those territories south of the Naaf River. While many did return, others remained behind in Chittagong and CHT districts. The British policy and the subsequent process of return of the Arakanese exiles, esp. the hard-working wet cultivating Rohingya people, facilitated the cultivation of vast territories within Burma, which had hitherto remained barren and uncultivable. This enriched the coffer of the British Government through collection of revenues and taxes. Many descendants of the exiled Rohingyas (or Ruhis of Chittagong) would also become seasonal laborers in Arakan.
Today, the bulk of the ethnic minorities that live in the Chittagong Hill Tract districts are the descendants of those fleeing refugees from Arakan who fled the territory during Bodaw Paya’s extermination campaign. They are our Chakma and Marma people. (There are two other ethnic minority groups living in the CHT – the Kukis and the Tripuras. The former are also known as the Chins in Burma and Mizo in India; while the latter lives mostly in the Tripura state of India.)  Their history to the territory cannot be traced with any authenticity before that historical event of 1784. This does not mean that there was no migration of people over the hills; in fact, there was migration in those days of porous borders where geography was not often attached with politics, state and administration. Like any nomadic people, the hilly people had no permanent settlement to the territory – they moved to and fro between porous borders of today’s Bangladesh, Tripura (India) and Burma. Their migration from outside, much like the Ruhis of Chittagong and CHT, cannot be traced before 1784.
Since the British rule of the territories dating back to 1826, many Bengali Hindus, Buddhists and Muslims have moved to the CHT for a plethora of reasons, including administrative jobs, logging, trade and commerce, a trend that was to continue well unto the Bangladesh period with development of industrial infrastructure there.
After the emergence of Pakistan in 1947, the CHT was made part of East Pakistan. During the War of Liberation, its Raja (Tridib Roy) openly aligned itself with the Pakistan regime, thus leaving a strong sense of betrayal and mistrust between the local Bengali or Chittagonian people and the Hilly people. During the war of liberation and in the post-liberation era, many Bengalis were kidnapped and killed by the extremist elements of the Hilly people. [A close relative of mine was one such casualty who was kidnapped and later presumably killed, never to be found later.] Crimes of this nature continued unabated making the territory unsafe and insecure. Outside the towns, there was virtually no functioning of the government. The territory became impassable and unlivable for most Chittagonian and Bengali speaking people. They would be kidnapped, and often times killed, even when ransom money had been paid to the kidnappers.
The so-called Shanti Bahini comprising of armed hilly bandits and extremists demanded autonomy and they were aided and armed by anti-Bangladeshi forces from outside. With the assassination of Bangabandhu Sk. Mujib, as the political scene changed drastically inside Bangladesh, the Shanti Bahini had a new sponsor – India – to destabilize the country. This led to tense situation between the government of Bangladesh and the Hilly people, leading to the deployment of the BDR and Army. The era of instability persisted during the military-supported governments of Zia and Ershad when hundreds of soldiers and officers died fighting against the criminal hilly terrorists.
After the overthrow of the military dictatorship, the situation improved somewhat, especially with the signing of peace treaty in 1997 under the first Hasina administration which stipulated total and firm loyalty towards the country’s sovereignty and integrity for upholding the political, social, cultural, educational and economic rights of all the people living in the hilly region. Unfortunately because of its demography and geography, the region continued to see infiltration of arms from outside, which inevitably have gone to forces that are destabilizing the region. Thus, even to this day, criminal hilly gangs who are opposed to the peace treaty and armed by anti-Bangladeshi governments and NGOs continue to harass the local police, BDR and military outposts, and kidnap and kill Bengali-speaking population, including members of the local and foreign NGOs that work on various projects aiming to improve the economic and social condition there.
In the last two decades, the CHT has also seen the incursion of narcotics and harmful drugs from Burma and India. Outside drug-traffickers, the territory has also become a natural hideout for many refugees and secessionist groups from Burma that are opposed to the SPDC oligarchy. As noted elsewhere, some of the Arakan National Congress (ANC) member parties are terrorist organizations (e.g., ALP) and are heavily involved in drug trafficking.  It is worth noting that ANC is a racist, chauvinist, ultranationalist Rakhaine organization that opposes to Rohingya human rights. In the past they have carried armed excursions from the CHT against the hated SPDC regime ruling in Burma.
In recent years some NGOs have emerged with ulterior motives that are at odds with aspirations of the people and territorial integrity of Bangladesh. No place offers them a better venue than the Hilly Districts where a sizable number of ethnic minorities live. They want withdrawal of Bangladesh Army that has preserved the territorial integrity. They want enactment of fascist ghettoization laws that would confine a particular ethnic or religious group into living in enclaves or reserves. They want forced removal of Bengali Muslims and Hindus from the hilly districts. It goes without saying that such demands are unrealistic and are sure recipes for dismemberment of Bangladesh. Their anti-Bangladesh activities are also bolstered by some human rights activists with foreign affiliations whose agenda includes weakening the sovereignty of Bangladesh. Not to be forgotten in this context are also some local players that are opposed to the current government. The latest unrest in the CHT may well fall into their scheme to destabilize the government.
As Bangladesh government renews its pledge for harmony, territorial integrity and stability, it cannot afford to appear weak against forces that threaten its very existence. Any measure that offers exclusion over inclusion, ghettoization over pluralism, discrimination over equal opportunity is undesirable and must be avoided.
As hinted earlier, economics has been a key driver shaping the demography within our planet. And Bangladesh (whose GDP owes much to the foreign remittance of her economic labors working overseas) with scarcity of land is no exception to that grand rule. In the post-liberation period, with the sharp growth of job opportunities within the hilly districts, some Bangladeshis have settled into the CHT. Many hilly people likewise have found jobs in the planes of Bangladesh, away from their traditional homes in the hills. This is quite natural for a country whose constitution allows for pursuit of freedom of movement, employment, economic prosperity and happiness for all. With a high fertility rate among Bengalis and Ruhis, it is no accident that they are a majority in some Hilly districts today.
The Hilly people are aware of these trends and have immensely benefited from the overall economic prosperity of the region. Most of them are against the extremists within their community. They also understand that they are the best protectors and preservers of their language and heritage, something that is becoming rather difficult for small minorities in a global economy of our time. In that balancing act between preserving cultural heritages and ripping the benefits of economic prosperity they would be better advised to follow the American/Canadian Amish example as opposed to that of the Native Americans living in the Indian reservations. 
In closing, to qualify as an aborigine a member of an indigenous people must exist in a land before invasion or colonization by another race. More stringent definitions require that the aborigines have resided in a place from time immemorial; i.e., they are the true sons and daughters of the soil.  From this definition, the Koori, Murri, Noongar, Ngunnawal, Anangu, Yamatji, Nunga and other aboriginals in Australia, the Maori of New Zealand, the Uyghurs of Xinjiang Autonomous Region in China, the Chechens in Chechnya of Russia; the Siberian Tatars, Khanty, Mansi, Nenets and Selkup people of Siberia in Russia; the Native Indians of the USA and Canada, Eskimos of Canada and few other races in Central and South America are the true aborigines (or more correctly, aboriginals) of our world.
It is not difficult to understand why the British anthropologist T.H. Lewin (1839-1916) did not consider the tribal people living in CHT as aborigines.  The brief analysis above also confirms that view. Thus, the Mongoloid-featured hilly people are as much settlers to the CHT as are the Chittagonians/Ruhis and other Bangladeshis living there. Calling these latter people “settlers” while calling the Mongoloid featured Hilly people as the “adibashis” or aborigines would be false and insincere! Simply put: all the people living in the CHT are the adhibashis (residents) there.
Notes:. A Kuki website claims: “There are eleven ethnic multi-lingual minorities in the greater CHTs. They are Bawm, Pangkhua, Lushai, Khumi, Mro, Khyang, Chakma, Marma and Tripura. They have been divided in to three groups. The Bawm, Pangkhua, Lushai, Khumi and Mro, Khyang are Kuki-Chin or Kuki group. The Tripura, Riang are Tripura group and the Chakma, Marma, Tonchangya, Chak are Arakanese group. These groups differ from each other in terms of languages, customs, religious belief and patterns of social organization. The population of the hill people in the CHT is divided into as many as 3 groups who the numerically superior ones are Arakanese group and the second are the Tripura group. The Kuki group are the third in numerical strength. According to Prof. Bessaignet, among the Arakanese group, the Marma came in the CHT leaving the plain areas in 1826. The Tripura came in the CHT from the Tripura state of India. Kuki group, are called themselves as Tlangmi or hill people (they are Bawm, Pangkhua, Lushai, Khumi, Mro, Khyang). They are known as Chin in Burma and Mizo in India. The Kuki group linguistically and culturally differed from other valley-living people or Jumma (Arakanese and Tripura groups). They belong to the Kuki-Chin branch of the Tibeto-burman language family. They are unbriddled freedom nation. They live on the ridge of hills. They even used to choose different habitats for themselves for living from the early days of their community-life. So British administrator Captain T.H.Lewin designates them as ‘Tongtha’ (child of hill). According to Dr. Shelly – The Bengali movement into the CHT date back to the 17th century when braving the natural disadvantages, a small number of Bengal‘s made their abodes in the inhospitable terrain of the region on an invitation of the Chakma chief.” . http://tinyurl.com/yaozwew . For American reservations, see, e.g., http://tinyurl.com/yaz3kd2 and http://tinyurl.com/y93u7mr. For life as an Amish, see, e.g., http://tinyurl.com/6kc9v5 and http://tinyurl.com/pjqj3 . See, e.g., http://tinyurl.com/yekg826, and the article by A. M. Serajuddin –” The Chakma Tribe of the Chittagong Hill Tracts in the 18th Century, Royal Asiatic Society of Great Britain and Ireland, No. 1 (1984), pp. 90-98, http://tinyurl.com/yda95aj. . According to T. H. Lewin (1839-1916), British ethnologist and anthropologist, the Chakmas and Mongoloid people of CHT are not aborigines. His famous book is: Wild Races of the Eastern Frontier of India, http://tinyurl.com/yenzfyr; http://tinyurl.com/yeuohev.