We have the current of integration $\delta_{X}\in D_{2n}({X^{\rm an}})$ given by $\delta_{X}(\alpha)=\int_{X}\alpha$ for $\alpha\in A_{c}^{2n}({X^{\rm an}})$. More generally, we define the current of integration along a closed $s$-dimensional subvariety $Y$ of $X$ as the push-forward of $\delta_{Y}\in D_{2s}({Y^{\rm an}})$ to ${X^{\rm an}}$. By abuse of notation, we denote this element of $D_{2s}({X^{\rm an}})$ also by $\delta_{Y}$. By linearity in the components, we define the current of integration along a cycle on $X$. If $W$ is an open subset of ${X^{\rm an}}$, then we get a current $\delta_{W}\in D_{2n}(W)$ by restricting $\delta_{X}$.