Class Imbalance is the situation where the distribution of observations across known classes are skewed or biased. One of the classes has either an unusually high or low number of observations.
An application-oriented question on the topic along with responses can be seen below. The best answer was provided by Ransingh Satyajit Ray and Sourabh Nandi.
Applause for all the respondents - Ransingh Satyajit Ray, Glory Gerald, Sourabh Nandi, Sanat Kumar.