There are 40 or more megacities in the world with more than 10 million inhabitants. Each has a different, but highly elevated chance of becoming incubators of cascading superspreader events for infectious diseases. Which city is most at risk? How can these risks be mitigated? What does it mean for the future of such cities?
In an attempt to limit a potentially highly complex analysis to something everybody can consider at face value and make up their mind about (or even input their own values based on their subjective opinion), I looked at only six main factors. Those factors are: Population size, Health system quality, role in international or domestic Transportation, Innovative rank, Transparency, and Pandemic readiness/response.
I also wanted a sketch of the analysis to come out as soon as possible, in order to foster more of the necessary discussion of what to do about these massive global policy, public health and humanitarian choices we face. This cannot be just a specialist discussion among world leaders. Never before in history have we had such a large population of educated, resourceful citizens that have had so much time.
The infographic below gives a rough overview of the pandemic risk on a city basis, some more detailed figures are also included, and there is a methodological note at the end. The final analysis, including much more data on post-Corona risk over the next decade, complete with a set of scenarios (scenario thinking is the only appropriate method given that the world impact is highly uncertain at the moment) will be included in my upcoming book, Pandemic Aftermath, in sale from 1 July 2020 and in pre-order from 1 June.

Risk mitigation in megacities
Risk mitigation in megacities (and in the world) is, unfortunately still at an early, immature stage. Most megacities who have already been affected felt like they were taken by surprise. Some were somewhat justified earlier in 2020, but at this point (April 2020), the surprise could only be because of lack of common sense as well as a lack of a modicum of foresight, or finally, plain denial (for political or other reasons).
The main mitigating strategy at the moment is social distancing as well as mass scale stay-at-home orders, or even in a few cases, unprecedented mass quarantines on a national, regional, city or local level.
Foreign aid’s role in the corona response
A little discussed strategy as we move ahead in the timeline of the spread of the virus would be to contain the virus first in countries with a high score on the health security index and who also have a strong history of foreign aid (countries in Northern Europe and Northern America), so that they could be freed up to contribute to the containment and treatment effort elsewhere in the world. The WHO seems to be mouthing such a strategy, but it gets lost in all the noise surrounding the politics of national response in each country.
The role of China
Of all things, China, where the crisis first escalated, has mounted an enormous combination of trade in personal protective equipment, humanitarian aid relevant to the coronacrisis as well as a public relations campaign. This is interesting in the context of analysing the situation of megacities only insofar as China has the largest proportion of megacities of any country. Will they be able to keep operating these cities without significant lockdowns in the time to come, despite their sheer size? Will the Chinese model of containment work for the second and third waves of the outbreak and will the Chinese experience inform other cities’ ability to cope?
The missing voices of the US and the EU
The US as well as the EU are two notable institutional frameworks which seem unable to get out of their myopic inward focus at the moment, an unprecedented situation that undoubtedly will cascade the world into uncharted territory, especially if it continues over the next months of 2020.
The scale of the needed humanitarian response around the world is likely not to have any parallel in world history, even if we consider the Marshall Aid in the re-building of Europe after the second world war. Who will be in a position to mount such an effort? If the answer is a new actor or no actor, the world will change in unimaginable ways in a fairly short time, perhaps a decade or less. Again, the fate of megacities will be crucial in mediating the response needed.
The future of megacities
Even at this early stage it is becoming abundantly clear that the cascading risks of life as we know it in the forty something megacities around the world have increased drastically. That is, the perception of risk has changed, the risk was always there. In any case, I don’t see how we can sustain humanity’s progress if mass urbanization continues at the same rate of development in the next decade as it did in the one we just left. What does that mean?
There is going to be massive pressure to figure out another solution than growing already large cities into megacities. There will be a mass exodus even from smaller cities into suburbs and the countryside, but that is likely to be short-lasting, as the jobs may continue to be found in larger cities.
The unknown factor is to which degree distance work and technology might finally kick in, having had a thirty year period of being slowly introduced into to the workplace on a limited basis, and usually only for one day a week, mostly in the knowledge intensive parts of the financial and IT industries.
The scant evidence from the past few months would indicate that there will be a wave of people and companies who will be able to sustain working from home on a continued basis, but the tension between office workers and home workers will continue.
It is also the case that the working class service workers scarcely will have the same chance to virtualize their commute and isolate themselves from contagion. This is likely to lead to increased tensions for the foreseeable future.
Reducing pandemic risk in megacities
In conclusion, the pandemic risk in the world’s megacities is significant and increasing, if not mitigated. We should be particularly worried about the most at-risk cities, what I’ve called the Pentaspreader cities of Manila, Jakarta, Mexico City, Mumbai, Caracas, Delhi, and Lagos.
Given their sheer size, lack of an adequate health security system, key role in international transport networks, situated in countries with poor records on transparency and/or governance, and limited innovative capacity to quickly recover, these cities do present exponential systemic risks to act as incubators of superspreading events for infectious diseases.
At this point, given the multiplicity of opportunities for spread of contagion through a super-critical size, scale and mass of large scale gatherings, practices, slum areas, public transportation network, and events (sports events, concerts, nightclubs, weddings, conferences, etc.) and mainly due to their density, megacities are a threat to the return to normalcy.
The only way to mitigate the risk they pose to a world who wishes to as soon as possible get out of social distancing, short of a vaccine or short of awaiting the gradual development of herd immunity, would be a global systemic approach to monitoring and mitigating contagion, specifically targeted at the challenge of megacities.
Over time, it is entirely possible that we might conclude that this type of monitoring and mitigation effort is not possible, at which point we would have to rethink the wisdom of allowing the explosion of megacities which is currently ongoing around the world, especially in emerging economies.
Methodological note
In the above, I have assumed that one can to a back of the envelope assessment of pandemic risk on a city basis, simply based on scoring six factors: Population size, Health system quality, role in international or domestic Transportation, Innovative rank, Transparency, and Pandemic readiness/response. The reason for choosing these is fairly obvious and constitutes a minimum set of basic predictors. Many other factors play a role, but if you had to choose six, this would be my suggestion.
If I had to defend why innovation plays a role, just consider how much is already having to be re-jiggered in advanced countries due to lack of preparedness. Not having ideas about how to do things in new ways, will severely limit your adaptability as a city in times of crisis.
However, a lot of the available data is on a country basis, which is why the initial analysis is just a broad estimate. The final analysis will be included in my upcoming book, Pandemic Aftermath, in sale from 1 July 2020 and in pre-order by 1 June.
For simplicity each factor has a value of 1, so that a major economic hub is -1, for instance, given that it adds to the stakes in terms of the degree of mobility its citizens have—increasing their chances of contagion (measured by how much of a transportation hub they are). We also use a neutral position, e.g. neither (– ) nor (+), assuming that the city doesn’t differ from others on this parameter in any significant way.
The exception is related to the top ten megacities in terms of population (the most salient factor in defining them as a megacity), which we will give -2 on our scale, given their enormous, almost insurmountable challenge should they have a significant outbreak.
We also graded the national or city governments’ response to the pandemic (mostly on speed in terms of implementing public health efforts to counter the pandemic). Pandemic response also has a potential for a +/-2, because of the way an efficient response to crisis generally seems to mediate and protect from a negative outcome.
Failed states will get -2 on transparency and innovation and (generally) on Pandemic response/readiness. If the city is only a national transportation hub, I’ll give them a neutral score regardless of the city’s size, given the outsized importance of imported infections in the Covid-19 transmission patterns so far.
Below, I have included the initial scores for the full set of megacities used for this preliminary analysis. The complexity of synoptically scoring, comparing and tracking risks in 40+ megacities, even if we are using as little as six varibles, should now be apparent. This is only a small part of the overall task the world now faces.

Not yet included in this post is my re-analysis of these risks only using available quantitative indicators (e.g. discounting subjective evaluation). Stay tuned for that in the book.