[Quicktake] Easing the lockdown and identifying the “at risk” regions

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6th May 2020

Pradeep Kumar

Associate Professor, University of the Witwatersrand, South Africa

Email: pradeep.kumar@wits.ac.za


Date: 06th May, 2020; South African National Lockdown Day 41
After about six weeks of national lockdowns globally; governments and governing structures at the city, state, region, and national levels are now considering easing the lockdown measures in a phased manner.

I will cite two examples here – South Africa and India.

1) South Africa has embarked on Level 4 lockdown starting 01st May, 2020, after a five-week Level 5 national lockdown. One major “ease” in Level 4 is that the public transport (mini- and midi-bus taxis) is now available at all times (except curfew hours; 70% seating capacity) as compared to restricted timings during Level 5. Buses are allowed to carry up to 50% of their carrying capacity1. This is a critical change as minibus taxis in South Africa, pre-COVID, serviced 2/3rd of South African households and transported over 1/4th of the population daily2.

2) India has extended the current lockdown to the ‘red zone’. However, the lockdown has been eased in ‘orange’ and ‘green’ zones with these zones classified on the basis that no new case is identified in the last 14 and 28 days, respectively3. In the red zones, no economic activities are allowed, with government providing door-to-door facilities. In the orange zones, limited public transport and farm harvesting are permitted (except in hotspot areas). In the green zones; public transport (buses up to 50% carrying capacity) and micro, small, and medium enterprises may operate business4. Further easing of lockdown regulations for public transport (such as local trains and metro) may have significant impact on COVID-19 curbing measures. During ‘normal’ times, road and rail are major modes of public transport in Indian cities with the Delhi metro, Mumbai suburban trains, and buses in Bangalore each commuting over five million passengers per day5.

Both the South African and Indian strategies are based on the number of cases in a given time frame or the presence/absence of hot spots in a given area. Since testing has been the bottleneck of this pandemic6, there is one aspect which may assist governments to decide on “coronavirus-free” and “coronavirus-infected” zones/areas by sampling the virus in the public transport system.

This is primarily based on the evidence that the main transmission mode of coronavirus is via “respiratory droplets” with a size ≥5µm and hence may drop to the surface within 1 to 2 meters from the releasing source7. This becomes very important in case of public transport where the entire sitting area is just two meters e.g. minibus taxis in South Africa.

This may at first appear to involve extensive workforce since swabbing public transport is a strenuous process. However, with very simple and innovative solutions this can be performed by the service provider itself on a daily basis.

By placing samplers (e.g. liquid impingers, solid impactors, filters, or electrostatic precipitators8) strategically in the public transport (minibus taxis, buses, trains, and even e-hailing rides) at the start of the route and then collecting and submitting at the end of the day in a collection depot for testing.

This could give an indication of the infection status of that area/zone on a daily basis as well as in the community. This should not replace the testing and tracking but will definitely assist the local authorities in decision making.


[1] New road rules for South Africa during level 4 lockdown. BusinessTech, 5th May, 2020. https://businesstech.co.za/news/motoring/395238/new-road-rules-for-south-africa-during-level-4-lockdown/ (Accessed on 06th May, 2020).

[2] Public transport inequality. Mail & Guardian, 25th Feb, 2020. https://mg.co.za/article/2020-02-25-public-transport-inequality/ (Accessed on 29th April, 2020).

[3] Lockdown 2.0: What are red, orange, green zones? Times of India, 16th April, 2020. https://timesofindia.indiatimes.com/india/lockdown-2-0-corona-battle-to-be-fought-in-red-orange-green-zones/articleshow/75172569.cms (Accessed on 30th April, 2020).

[4] Red, Yellow, Green Zones for Lockdown 3.0: Full list of districts, relaxations and activities allowed. India Today, 01st May, 2020 (updated 04th May, 2020) https://www.indiatoday.in/india/story/red-orange-green-zones-full-current-update-list-districts-states-india-coronavirus-1673358-2020-05-01 (Accessed on 06th May, 2020).

[5] Post Covid-19 lockdown, will India’s public transport systems be able to maintain social distancing? Scroll.in, 28th April, 2020. https://scroll.in/article/960063/post-covid-19-lockdown-will-indias-public-transport-systems-be-able-to-maintain-social-distancing (Accessed on 30th April, 2020)

[6] Scientists seek solution to coronavirus testing bottleneck. Modern Healthcare, 21st April, 2020. https://www.modernhealthcare.com/patients/scientists-seek-solution-coronavirus-testing-bottleneck (Accessed on 29th April, 2020)

[7] van Doremalen V, Bushmaker T, Morris DH, Holbrook MG, Gamble A, Williamson BN, Tamin A, Harcourt JL, Thornburg, NJ, Gerber SI, Lloyd-Smith JO, de Wit E, Munster VJ. Aerosol and surface stability of SARS-CoV-2 as compared with SARS-CoV-1. New Eng J Med 2020;382:1564-1567.

[8] Verreault D, Moineau S, Duchaine C. Methods for sampling of airborne viruses. Microbiol Mol Biol Rev. 2008;72(3):413‐444.