When we talk about the ill effects of Colonialism, not only were the colonial powers involved in oppressing the local populations and plundering wealth and sources (e.g., the British plundered and looted 45 trillion dollars from India) but it also turned the different ethnic groups or the homogenous groups against one another and created more mess afterwards. The colonial masters left behind every essence of morality to oppress and brutalize the local populations. Regarding the messy situation when the colonial masters left, three examples are very notorious... …PALESTINE, HONG KONG and KASHMIR.
Palestine was under the British Mandate after the World War I, but things would start getting tough for the Palestinians, who were brutally repressed and not given their due share. British crushed a rebellion in 1930s when Palestinians rose against them. The Balfour Declaration of 1917 was a smack on the faces of Palestinians and their right to self-rule, and then in 1948, the Jews would take over and instigate NAKBA, rendering nearly 700,000 Palestinians homeless, all thanks to the oppressive policies of colonial Britain.
Hong Kong was under British control for a 99 year lease till it became a territory of mainland China in the late 90s. What the British failed to realize was that Hong Kong in these 99 years had developed a different identity than China, and it was bound to create a mess. Recent protests are a manifestation of those ill meted policies, where natives of Hong Kong have come out in droves to resist an extradition law passed by Mainland China and approved by the leader of Hong Kong.
Kashmir too was a part of British Raj when India was a colony, but it would become a mess and a bone of contention between Pakistan and India since the inception of these two countries. Both countries have fought three wars in the region and is one of the most militarized zones in the world. Nearly two years ago, India gave the Illegally Indian Occupied Jammu and Kashmir (IIOJK) admittance in the Indian Union, which Pakistan protested. All the dominos of such unprecedented moves and policies were instigated by the first domino that fell when The Britons pushed it.
Regarding conflicts between homogenous groups and different ethnicities, one must check the SYKES-PICOT AGREEMENT drafted between France and UK during the days of First World War. This agreement made the areas of the Middle East among the French and the British. According to this agreement, France would get the Northern zone including Syria and Lebanon while Britain would get the Southern Zone after the War, which included Mesopotamia (modern day Iraq and Kuwait), Jordan and Palestine.
A= French Zone, B= British Zone
Both French and British would try to assert their influence in the region. The British demarcated the borders of Iraq and Kuwait, and the French tried to demarcate the borders of Lebanon in such a way that that Lebanon would have a Christian majority population, nonetheless a failed attempt.
Repercussions of the Sykes-Picot Agreement
Iraq's borders were demarcated in such a way that the different ethnic/religious groups, Sunnis, Shias, Kurds etc. would have endless conflicts, and because of the way their borders were demarcated with Kuwait and the allocation of the oil fields along with Iraq's restricted access to The Gulf, Iraq would attack Kuwait and hence the bloody Gulf war took place in the early 90s.
French attempt to demarcate Lebanese borders would become a source of strife and would later develop into the gruesome 15 year civil war in the country. The civil war started in 1975 and went on till 1990, devastating the status of Lebanon as a peaceful place with a rich intellectual tradition. The ramifications of the War are still felt to this day.
Nearly all the issues/conflicts in past colonies were due to the ill-conceived policies of the then colonial masters. Recently, France gave out a statement that it will never apologize for the brutalities it committed in colonial Algeria, where it killed more than a million people. French General Marcel Biegard has even defended the torture and atrocities committed in Algeria by the French.
Malek Bennabi, the famous Algerian intellectual of the twentieth century, writes in ‘The Chaos of the Western World’: "Colonialism that materially kills the colonized also destroys morally the Colonizer".
Bennabi also criticizes the colonial powers for bringing materialism to the colonized lands, which inhibited the spiritual essence and aspects of life. Bennabi criticizes Europe that instead of guiding humanity through its torch of civilization, it set flame to the colonial world.
The colonizer, in his injustice, forgets justice and loses the true element of civilization within him. While de-civilizing, brutalizing and degrading the colonial subjects, he degrades himself. In the words of Martinican poet Aime Cesarie, "Colonialism works to de-civilize the colonizer, awakening within him lust, violence, racial hatred and moral relativism".
Colonialism has produced a long list of profound ill-effects in the colonies, but I just restricted myself to a few examples of the inglorious errors and crimes of the colonial powers, to enlighten the readers and give them an overview of the ill and devastating effects of colonialism.