Why is a C-I bond a non-polar covalent?

Electronegativity (EN) is a measure of the ability of an atom to attract bond-pair electrons.

Consider a covalent bond X-Y. If X is more electronegative than Y, electron clouds are drawn more to X than Y. X becomes slightly negative and Y becomes slightly positive. The bond is said be polar. The greater the difference in electronegativity the two atoms, the more polar is the covalent bond. On the other hand, if X and Y have equal electronegativity, the electron cloud will be even distributed in X-Y bond, and X-Y bond is thus non-polar.

According to Pauling scale of electronegativity, the electronegativity of C and that of I are 2.55 and 2.66. (In most common textbooks in AL, they are both quoted as 2.5.) Since the difference in electronegativity of C and I is insignificant. The C-I bond is very weakly polar and approximately non-polar.
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