The signal of a stochastic gravitational wave (GW) background has been sought for several decades and has just come within the observational reach due to the pulsar timing array. While several sources of GW background have been analysed in the literature, the phenomenon of scalar-induced GW emerges as a simple and inevitable candidate. Scalar-induced GW are highly sensitive to primordial non-Gaussianity, such as three-point and four-point correlations of primordial scalar perturbations. 

In this talk, I shall discuss the unique signature of chirality imparted to scalar-induced GW by the parity-odd component of the four-point correlation, the trispectrum. The degree of chirality in GW allows us to impose an independent limit on the strength of the parity-odd trispectrum and compare against observational bounds. Certain scale-dependent features induced in the spectral density of chirality of GW capture the interplay of these two distinct markers of parity-violation in the universe. The results of this analysis supplements our knowledge of primordial non-Gaussianity elicited from CMB and galaxy surveys. I shall conclude with a brief outlook of our results in light of ongoing and upcoming observational missions.