Dipankar Gupta explains the difference between inequality and difference while clarifying the stratification concept. Stratification is often interpreted as the arrangement of groups in a vertical or hierarchical manner, which is based on inequality. Dipankar Gupta explains that even though some systems such as wealth, income, social status, etc. are hierarchical, the stratification concept cannot be generalized like that.
Some systems are horizontally arranged, which means the groups are not inequal, rather they are different. For example, if we take the stratification of languages, no language is superior to others. So, this particular system is based on difference and not on inequality. Religions, nationalities are some other examples of such a form of stratification.