Low testing hints at extension in curbs

India’s curve, yet to flatten vis-à-vis other countries with similar or more conservative plans to ease restrictions, still points to ‘exponential growth’, despite much fewer tests

The government on Friday announced an extension in the nationwide lockdown — enforced to prevent the spread of coronavirus, and subsequently extended till May 3 — by another two weeks, till May 17, with curbs targeted at cities and “hotspots”. It gave the go-ahead to re-opening of businesses in areas designated as green zones and orange zones — mostly rural areas.

Technically, this makes lifting of restrictions even in the red zones possible after May 17. However, a comparison with some countries that have experienced a far worse spread than India gives two insights.

First, India’s curve is yet to flatten vis-à-vis countries that have similar or more conservative plans to ease restrictions. There have been marked flattening of the curve in Turkey, Singapore, the US, and France. Asian peers are experiencing a similar fate, with the curve refusing to get horizontal. India is showing only a slight indication of flattening. And second, the curve has remained at 45 degrees to the X axis — meaning exponential growth — despite the fact that India among the group has tested way fewer people. France’s number of tests has been nearly 15 times India’s number.

In the adjoining graphs, for each country, new cases are plotted against existing stock of cases till a particular date, and the line traces time. New cases are usually quite small compared to the latter, which keeps growing. However, both the variables are plotted on a logarithmic scale, which makes their growth comparable.

To cut the jargon, this method gives a straight line at 45 degrees to the X axis for a perfect exponential growth. Please note that the number of days for doubling could be different for different countries, and this graph does not show that rate. It simply shows whether there is still exponential growth or if it has subsided.

India, along with other Asian nations, is still behind other developed countries in this respect. Yet, France is lifting restrictions after May 11, which is not far from India’s current date of easing curbs. Singapore, on the other hand, is revoking its “circuit breaker” (curbs) on June 5, despite having flattened the curve and controlled deaths.

At the same time, if testing is ramped up in India in coming weeks, there is a strong likelihood that cases will multiply fast. This will put more pressure on the curve to remain linear at 45 degrees to the X axis — that is, exponential. At 700 tests per million — less than 0.1 per cent — India is nowhere near the advanced economies that have tested more than 1 per cent of their population.