What symbolic meaning do the Circles of Hell most likely represents in the Inferno

These circles of hell most likely represent the different levels of sin. The first level would include your most basic levels of sin (i. e. Gluttony, Greed, etc ...). As the levels go down further, the level of sin increase. This represents the further down the pit you go, the deeper you are, and it makes it harder to get out and redeem yourself.