Central parts of most Indian cities vulnerable to contagion2 min read . Updated: 18 May 2020, 12:33 AM IST
Delhi, Kolkata, and Mumbai have the highest shares of population living in high-risk wards according to an analysis of satellite data
India’s biggest cities have been effectively shut down for over 50 days, and for good reason. The top 15 most populated cities in the country have about 60% of confirmed coronavirus cases. But locking these so-called “red zones" indefinitely poses severe risks to the health of the Indian economy and threatens the livelihoods of millions.
As in other parts of the world, the biggest cities are also the biggest drivers of the economy, and their influence on the economy goes far beyond their stated share in the country’s gross domestic product (GDP).
Cities are vital nodes in the cross-country and cross-national supply chains, and shutting them down has a huge impact on other parts of the country.
As a recent study on the impact of shutting down Tokyo suggests, mega-cities have an outsized role in modern economies. Tokyo accounts for 21% of Japan’s total production, but the study estimated that Japan would lose 86% of its daily output if the capital city is shut for one month.
Opening up cities can, however, raise contagion risks. To balance the lives-versus-livelihood equation, policymakers will increasingly have to define no-go areas and green zones at a much more micro-level.
One way to do this would be to focus on localities with high caseloads. But given that the actual spread of the disease remains unknown and, the fact that it could spread quickly to other areas, a more effective way might be to focus on areas where the risks of contagion are the highest.
And, one approach to measure such risks would be to measure the extent to which people and crowds gather in any particular locality.
Using this approach, a team of data scientists at the Delhi-based data analytics startup, Sociometrik, has come up with a micro-level risk index for each 1 sq. km grid in India’s worst-hit cities.
The risk index is based on satellite data on human settlements, density of congregation spots (such as places of work and recreation), and density of road and transit networks. [Chart 1a]
The risk scores are not comparable across cities, but allow us to zoom in on the areas in each city facing relatively higher risks. Typically, central parts of cities face the maximum contagion risk, while suburbs face lower risks.
For instance, GTB Nagar and Kotla Mubarakpur in central Delhi are among localities with the highest risk scores. In Mumbai, Khar West, Dadar East and Parel have the highest risk scores. In Ahmedabad, risk scores are highest in Raikhad and Gulbai Tekra.
Other large cities, such as Bengaluru and Hyderabad, have lower case-loads than others at the moment. But some parts are more at risk compared to others. In Bengaluru, Basavanagudi and Marenahalli face the highest risk. In Hyderabad, Somajiguda and Moosarambagh face the greatest risk, based on the risk index developed by Sociometrik.
Such a risk model, when combined with other parameters such as mobility of people inside a neighbourhood, information on marginalized groups based on demographic data, and data availability of public infrastructure, could help city authorities and policymakers understand the geography of risk better.
Such an approach will also help in contingency plans for future pandemics.