Ratio of ${\mathrm{\Delta }}_{\delta T_{\text{b}}}^2$ to ${\mathrm{\Delta }}_{\delta \delta }^2$ obtained from simulations during EoR. The top panel shows ${\mathrm{\Delta }}_{\delta T_{\text{b}}}^2/{\mathrm{\Delta }}_{\delta \delta }^2$ as a function of k at different redshifts. These correspond to our fiducial GRIZZLY model which is also shown in Fig. 2. The bottom panel shows evolution of ${\mathrm{\Delta }}_{\delta T_{\text{b}}}^2/{\mathrm{\Delta }}_{\delta \delta }^2$ at k = 0.05 h Mpc⁻¹ as a function of neutral fraction. Different curves stand for different reionization scenarios generated using GRIZZLY by varying α_S and M_min. The black curve represents our fiducial GRIZZLY simulation which corresponds to α_S = 1 and M_min = 10⁹ M_⊙.