  The tensions between the values of Hubble constant obtained from the early
and the late Universe data pose a significant challenge to modern cosmology.
Possible modifications of the flat homogeneous isotropic cosmological
{\Lambda}CDM model are considered, in which the Universe contains dark energy,
cold baryonic matter and dark matter. They are based on general relativity and
satisfy two requirements: (1) the value of the Hubble constant, calculated from
the value of the Hubble parameter at the recombination by the formulas of flat
{\Lambda}CDM model, should be equal to 92% of the one based on low-reshift
observations; (2) deviations from the {\Lambda}CDM model should not lead to
effects that contradict astronomical observations and estimations obtained
thereof. The analysis showed that there are few opportunities for choice.
Either we should consider DM with negative pressure -\r{ho}_{dm}c^2<<p_{dm}<0,
which weakly affects the evolution of the Universe and the observed
manifestations of DM, or we should admit the mechanism of generation of new
matter, for example, by a decay of DE.
