Synchrotron spectral index and corresponding uncertainty maps obtained using the QUIJOTE MFI 11 GHz map alone in replacement of QUIJOTE MFI combined maps of 11 and 13 GHz are shown in the first and second panels, respectively. The similar plots of synchrotron spectral index and corresponding uncertainty maps when we use QUIJOTE MFI 13 GHz data alone are shown in the third and fourth panels respectively.