When Covid-19 enters India’s slums
The spread of the coronavirus disease (Covid-19) in India’s slums will be even faster than in the non-slum areas we seem to be tracking so far.
Overcrowding, lack of clean water, poor sanitation, social dependency, larger number of human contacts, low disease immunity of dwellers, besides poor medical facilities make for tremendous speed and size of virus transmission in slums. The poor quality of air in urban slums are a common cause for respiratory diseases that further reduces the respiratory tract’s ability to shut the coronavirus down. Our research at the Centre for Sustainability has explored the implications of the unique social infrastructure of slums in India on the significant role it plays in the spread of Covid-19.
India is home to about one-third of the global slum population, with an average of one in six city residents living in slums where population densities vary between 277,136 persons per square kilometre (sq km) in Dharavi to 125,000 persons per sq km at the Rasolpoora slum in Hyderabad. Slums are an integral part of the city’s economy as that is where a majority of workers and domestic help stay.
Various authors have estimated that reproductive ratio (R naught) for Covid-19 is somewhere between two and three, and that it would be about 20% more in the case of India’s slum population. This means that the reproductive ratio of Covid-19 would range between 2.4 to 3.6 in Indian slums. R naught applies to a situation where everyone in the population is susceptible, and no control measures are taken. It gives us the number of new cases that an existing case can generate over time, on an average. If R naught is below one, the population of infected individuals will get smaller and smaller over time. But in a fictitious population, where one infected person infects three other individuals on average — A gives it to three people (B, C, and D) and these three people give it to three more people each — R naught is equal to three.
Indeed, the spread of Covid-19 depends on the susceptible population that an infected person is going to encounter per time unit — let us say per day, times the average duration of infectiousness in days, times the average probability that transmission will take place per unit of contact. In order to ascertain if Covid-19 is going to spread fast and wide, besides the R naught, we need to also know the serial interval of the spread. The serial interval is a measure of how fast the disease spreads from one person to the next, and this changes across localities and time.
We took a fictional case of 1,000 individuals in a Delhi slum who have never been exposed to the coronavirus. While R naught is three, we find the current serial interval in a moderately dense Delhi slum zone to be close to about 7.5 days. So, in the first 7.5 days, the infected person infects three people, and they develop the disease.
After 7.5 more days, each of these individuals infects three more people, and they, then, develop the disease. So, we now have nine infected people, and, after 7.5 more days, each one of those nine people infects three people each. Similarly, after another phase of 7.5 days, each 27 infected individuals infect three people each, which means 81 individuals. Add the first individual with the next three, then the next nine, then the next 27, and then the final 81. And, in a month, you have 121 new cases per 1,000 people.
This simulation indicates the high speed of spread of Covid-19 in all the slums in Delhi/India. Assuming such a community transmission occurs, we are in for a disastrous situation, for which the precautionary measure of maintaining physical distance between individuals in slums appears impossible for at least three reasons.
First, the sheer lack of living space in slums makes physical distancing of people impossible. The average slum household size in India is typically three times larger than a non-slum household, but members only have a few square metres to live within it. The average population density is about 1,000 people per square mile but in the slums, it is 10-100 times higher.
Second, the lack of adequate social security by the State or private insurance makes the fight against Covid-19 even more complex. It leads to the impossibility of expecting slum dwellers to socially distance themselves from the only insurance policy they usually have — their family and social networks.
Third, with an average of 88.7% of households in India having access to improved sanitation services under the government’s Swachh Bharat Abhiyan, the situation is better than it was before 2014. However, access to sanitation is still low. Our research indicated that 70.30% households in Delhi slums do not have improved sanitation. The situation is much worse in Dharavi with one toilet per 1,440 residents. How do people maintain social distance in such situations? Moreover, the ongoing Covid-19 pandemic survives even longer than three days in faecal matter, which makes crowding around toilets and living amid bad drainage a major threat at this time.
And so, instead, we propose the immediate roll-out of the following urgent measures.
First, the focus must shift to proactive testing for asymptomatic and symptomatic Covid bearers within the most vulnerable, high population density pockets of our population. There are genuine capacity issues but this would mean that we need mandatory testing of Covid-19 of all slum inhabitants across India. Quarantine the asymptomatic and symptomatic bearers of the virus in slum zones in different isolated locations.
Second, we need to ensure that slum residents do not have to crowd around sanitation facilities. Install temporary or mobile toilets.
Third, we must deploy tankers to immediately provide clean water to slums so they can maintain good hygiene.
Our research shows that 19.15% of inhabitants of slums in Delhi have no clean water sources. About 160 million Indians do not have access to clean water, and definitely not hand sanitisers.
And, finally, the only way individuals suffering from mild to severe symptoms from the slums will come forward is if they think the State or the health authorities can do something to help them. We must not make Covid-19 a social stigma.