  We consider the problem of gelation in the cluster coagulation model
introduced by Norris [$\textit{Comm. Math. Phys.}$, 209(2):407-435 (2000)],
where pairs of clusters of types $(x,y)$ taking values in a measure space $E$,
merge to form a new particle of type $z\in E$ according to a transition kernel
$K(x,y, \mathrm{d} z)$.This model possesses enough generality to accommodate
inhomogenieties in the evolution of clusters, including variations in their
shape or spatial distribution. We derive general, sufficient criteria for
stochastic gelation and strong gelation in this model. As particular cases, we
extend results related to the classical Marcus--Lushnikov coagulation process,
showing that reasonable `homogenous' coagulation processes with exponent
$\gamma>1$ yield gelation; and also, coagulation processes with kernel
$\bar{K}(m,n)~\geq~(m \wedge n) \log{(m \wedge n)}^{3 +\epsilon}$ for
$\epsilon>0$. Finally, we use coupling arguments with inhomogeneous random
graphs to deduce sufficient criterion for strong gelation (the emergence of a
particle of size $O(N)$).
