  The notion of a pseudo cluster tilting subcategory $\mathcal X$ in an
extriangulated category $\mathcal C$ is defined in this article. We prove that
the quotient category $\mathcal C/\mathcal X$, obtained by factoring an
extriangulated category by a pseudo cluster tilting subcategory, is a
semi-abelian category. Furthermore, we also show that the quotient category
$\mathcal C/\mathcal X$ is an abelian category if and only if certain
self-orthogonal conditions are satisfied. As an application, these results
generalize the work of Xu and Zheng in the exact category.
