Migrants are the backbone of India's urban economy, driving taxis, sewing clothes and building apartments for a daily wage that they send home to those left behind in villages.

New Zealand has struggled to fight off an infectious outbreak of the Delta variant, forcing Prime Minister Jacinda Ardern to move from its strategy of elimination through lockdowns to living with the virus with higher vaccinations.

Some health experts are warning that there is not enough data available from human trials to back up the drug's emergency use.