  We consider a six-dimensional $U(1)$ gauge theory compactified on
two-dimensional manifolds. The number of chiral fermions is determined by the
flux quantization number on the two-dimensional compact manifolds. Using the
Swampland Conjectures, we find constraints among the parameters of the theory:
the flux quantization number, the compactification scale, and the string scale.
Specifically, the Weak Gravity Conjecture and the Trans-Planckian Censorship
Conjecture give non-trivial bounds.
