@Borah:2018gjk; @Borah:2019bdi]. In most of such models there exists some exact or approximate discrete symmetries to stabilise the DM or to give rise to a long lived metastable WIMP.

In this work, we try to find a common thread linking the discrete symmetries in neutrino sector and DM sector. We consider the neutrino sector to have an exact $\mu-\tau$ symmetry while the dark sector has an exact $Z_2$ symmetry. We find a common source of breaking of these discrete symmetries through Planck scale suppressed operators by using the well known argument that any generic theories of quantum gravity should not respect global symmetries: both discrete and continuous [@Abbott:1989jw; @Kallosh:1995hi; @Hawking:1974sw]. Recently, this argument was used to realise light neutrino mass from Planck scale lepton number breaking [@Ibarra:2018dib]. Effects of such Planck scale breaking of discrete symmetries on light neutrino parameters was studied within the context of left right symmetric model a few years back in [@Borah:2013mqa]. Here we study the consequences of such Planck scale breaking of discrete symmetries on neutrino sector which generates non-zero $\theta_{13}$, as required by present neutrino data. At the same time, such breaking also makes it possible to realise the super-WIMP scenario by assisting the 