What are the distinctive features that make Salman Rushdie postcolonial writer?

There are many different ways to approach this question. 
One major distinction puts Rushdie in the postcolonial setting is how he is so profound
on the idea of national identity in a nation-less world.  The Colonial setting that
defined identity on the basis of European nations and "the West" controlling other parts
of the world is something that Rushdie truly challenges in his work.  Rushdie is more
concerned with how the individual constructs identity as a product of a world where the
Colonial powers are no longer evident, but their presence still lingers.  This is seen
in works such as Midnight's Children and writings featured in
Imaginary Homelands. Even his modern work such as
Shalimar the Clown features this dynamic between a life that is after
Colonialism, but still operates with part of one foot in it.  I would also say that
Rushdie's own experience with "nation" is something that makes his writing so intense on
the nature of postcolonialism.  Born in India at Partition, living in Pakistan, and then
England, only to find himself unable to live anywhere because of the Fatwa helped to
bring out the idea in his writing and thought that individuals are of a world that holds
both Colonial and Postcolonial tendencies.  In this setting, we, as human beings, step
across lines that used to be demarcate identity so thoroughly, but now are simply new
frontiers to be crossed.  This becomes one of the central points in Rushdie's collection
of essays, Step Across this Line.