Cluster decay of the superheavy nuclei $^{270-318}118$ has been studied taking Coulomb and proximity potentials as interacting barriers. This study is based on the concept of cold valley. Cluster decay half-lives and other characteristics are computed for various clusters. The predicted α decay half-life values are compared with other theoretical models and also with the sole experimental value. Plots connecting half-lives with the neutron number of the daughter nuclei as well as with the neutron number of the parent nuclei, strongly indicated neutron shell closure at $N = 184$. Also, we noted that proton shell closure occurs at $Z = 114$. From our studies, we noted that the nuclide $^{298}_{184}114$, which is doubly closed, is very stable and we could reach the inference that $^{298}_{184}114$ is the most probable nuclide to be the centre of island of stability.