Taxation inequity

Economics always use one word ceteris paribus which can be interpreted as all things be equal. But economics words only work in western world and not Nigeria . the issue of taxation is very important to an economy and if violated will hampered the growth of a country .I will suggest that African country should adopt the progressive taxation system and jettison regressive and proportion sytem of taxation thereby charging the rich more and the poor less . how can an individual receiving $40000 be given a tax base of 20% for instance and another individual receiving $5000 be given a tax base of 20% this is unfair and only happen in country like nigeria . economics laws are violated in nigeria and only work in advance countries.
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