The Hubble parameters measured by the Dark Energy Spectroscopic Instrument (DESI) DR2 baryon acoustic oscillation (BAO) observations show a significant discrepancy from the prediction of the standard cosmological model. This discrepancy, together with the long-discussed Hubble tension, may originate from large-scale inhomogeneities in the matter distribution. This interpretation is motivated by infrared galaxy surveys, which suggest that our galaxy resides within the $\sim 300\mathrm{Mpc}$ underdense region known as the Keenan-Barger-Cowie void. In this study, we apply a linear-order relation—relating the horizon-scale Hubble parameter inferred from cosmic microwave background observations and the local-scale Hubble parameter—to the $\mathrm{Pantheon}+\text{Type}$ Ia supernovae and the DESI DR2 BAO data. We show that a simple inhomogeneous cosmological model consisting of eight top-hat shells can consistently explain the Hubble parameters inferred from both observations. Based on the matter-density distribution, we also briefly discuss its possible impact on cosmological observables, including the magnitude-redshift relation, the kinematic Sunyaev-Zel’dovich effect, and the integrated Sachs-Wolfe effect.

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• Cosmological parameters
• Large scale structure of the Universe