In One Punch Man, the Hero Association's S-Class consists of the Earth's most powerful heroes. Even within this exclusive group, there are echelons of power, and higher-ranked S-Class heroes are typically superior to those below them. Although Rank 2 Tatsumaki is clearly stronger than someone like Rank 14 Tanktop Master, a strength hierarchy requires close analysis of similarly-ranked heroes' feats and abilities.
Source：https://www.cbr.com/strongest-s-class-heroes-ranked-one-punch-man/
