Measuring $H_0$ from low-$z$ datasets
  Adopting the low-redshift observational datasets, including the Pantheon
sample of Type Ia supernovae, baryon acoustic oscillation measurements, and the
tomographic Alcock-Paczynski method, we determine the Hubble constant to be
$67.95^{+0.78}_{-1.03}$ , $69.81^{+2.22}_{-2.70}$ and $66.75^{+3.42}_{-4.23}$
km s$^{-1}$ Mpc$^{-1}$ at 68\% confidence level in the $\Lambda$CDM, $w$CDM and
$w_0w_a$CDM models, respectively. Compared to the Hubble constant given by
Riess et al. in 2019, we conclude that the new physics beyond the standard
$\Lambda$CDM model is needed if all of these datasets are reliable.
