bar of metal has a mass 200 g and the certain weight mass remain the same when weighted at equator but weight decreases.why?

As we know that, mass is a fundamental quantity, whose value remains same at all places in the universe. 
As weight of a body = mass X acceleration due to gravity (g).  .........(1)
And as we know that the value of g is less at equator. Therefore, weight of a body decreases at equator.