Consider the Simple Symmetric Exclusion Process (SSEP) $\eta_t$ on $\mathbb Z^d$. Let $\Gamma_t=\int_0^t \eta_s(0)ds$ be the occupation time of the origin up to time $t$. In this talk I will discuss about the limit of $\frac{\Gamma_{tn^2}}{\beta_{d,n}}$ for some properly chosen $\beta_{d,n}$. I will first review results in the equilibrium setting, then report some progresses made in the non-equilibrium setting.