With respect to fuel cell prepared from H₂ and O₂ gases, the false statement is

It is free from pollution

The reaction occuring at anode is ${\mathrm{O}}_{2\left(\mathrm{g}\right)}+2{\mathrm{H}}_2\mathrm{O}+4{\mathrm{e}}^{-}\to 4{\mathrm{OH}}^{-}$

These take little time to go into operation.

This is more efficient than conventional method of generating electricity