Leon Grice
India's exponential increase
In this blog we look at India's COVID-19 trajectory which indicates an unrelenting path to eventual herd immunity. If it keeps going as it has been, India will hit a peak infection day on 1 December 2020. We present the Reff graph for India and we have placed that data into our own inhouse SEIR COVID-19 simulator for a scenario for disease spread. (Scenario does not equal prediction.)

So, the first thing to notice is that India has never had its Reff value below the redline Reff=1.0 so new daily cases have been on a consistent exponential upcurve. The India Government did put in place social distancing orders and the Reff declined in early August. Those orders have since been eased. On 3 September our method records India's Reff=1.3 and there are nearly 80,000 new cases per day. At these high rates of infection it is likely that India's medical systems are already saturated.
CloseAssociate's COVID-19 Simulator
Earlier this year we developed an online simulation tool based on the early SEIR modelling work done by University of Auckland. It is an interactive tool that allows simulations and scenario based forecasting. The Indian government or the Indian people may change social behaviours so these simulations should not be interpreted as predictions. That being said, we simulated India's COVID-19 trajectory about two months ago and today when we redid the simulation and we were struck how similar the simulation results were. The quantum and key dates have not really changed.
The graph of actual daily cases in the screenshot above shows an exponential growth shape which roughly corresponds to the simulation in the screenshot below.
India's simulated peak infection day - 210 million people on 1 December 2020

India's peak infection day (new daily cases) is simulated to be 1 December 2020 when 210 million people will become newly infected. (For data modellers you can see the inputs into our SEIR model on the left hand side of the screenshot.)
India's incidence of fatalities will peak at roughly the same time. As the disease spreads through the population through this period, India's herd immunity will increase and this simulation has the epidemic and infection rate reducing rapidly in February 2021. We haven't simulated fatalities or cumulative deaths in India because that is a function of many factors we have not researched.