Research says medium-duration travel bans are counterproductive, for they trap migrants in cities that are Covid-19 hotspots. As states impose fresh lockdowns of varying durations and intensity to arrest the second wave of the COVID-19 pandemic, a new study shows that medium-duration travel bans are counterproductive–they trap migrants in cities that are COVID-19 hotspots long enough to expose them to the virus, which they then carry to their home districts. These findings are based on the study of return migration out of Mumbai between March and August 2020, covering the first national lockdown and the subsequent “unlock” phases. The study also took into account the epidemiological data on the rise in infections in the home districts of the migrant workers. The study by the University of Chicago’s Energy Policy Institute, whose pre-print (non-peer reviewed) version has been published, reached the same conclusion for other developing countries such as Kenya, South Africa, Indones...