The note consists of two parts.
In a crude analysis, we have seen that the growth rate in the number of daily confirmed cases is roughly linear in activity index(from the mobility report of apple).
In a refined analysis, we have seen that while SEIR model does not reproduce the data well, SEIR model with time delay reproduces the data well. Furthermore, it is suspected the ratio of $\beta$(growth rate of number of daily confirmed cases) before and after lockdown might be square of the ratio of activity index before and after lockdown. We need to further examine the relation of $\beta$ and activity index in order to predict the number of confirmed cases.