Spark-induced Breakdown Spectroscopy was used for local fuel-air equivalence ratio measurements of premix ed methane-air mix tures by a discharge from an inductive ignition system in a constant volume cell. Elemental emissions of hy drogen Balmer-alpha line (H α ), nitrogen (N7 46) and ox y gen (O777) were ex perimentally observed in the v icinity of the electrode gap, using a lens-coupled spectrometer and an intensified camera. After optimization of the gating strategy , the spectral emission features, i.e. line intensity ratios and peaks width (full width at half max imum) ratios were analy zed and their relation with the local fuel-air equiv alence ratio at the spark plug was discussed, for operating pressures ranging from 1 0 to 20 bar.Results showed that a change in pressure and temperature did not affect the spectral emissions' atomic peaks ratios, as long as the density was kept constant. For tests at constant temperature and at constant pressure, the peaks intensity ratios showed a linear correlation with local fuel-air equivalence ratio, while peaks width did not show noticeable changes. When pressure was v aried, while keeping temperature and fuel-air equivalence ratio constant, a different behavior was observed: peaks intensity ratio were only slightly affected by pressure change, more prominently at fuel-rich conditions, while a peak broadening was clearly recognizable, as the peak width linearly increased with pressure.Moreover, an additional optical setup involving a fiber-optic spark plug was implemented with the aim to adapt the proposed diagnostic tool to engines in operando. Comparisons with the lens setup showed that the dev eloped technique is promising as a compact and v ersatile tool for applications inv olv ing local fuel-air equiv alence ratio measurements at different ambient conditions.