India's 50 million domestic workers already had it tough. Now the mostly female force of cooks, cleaners and carers must test negative for coronavirus and get vaccinated to keep earning, a crippling new cost of the pandemic.

COVID-19 infections have already topped 15 million nationwide, a tally only surpassed by the United States.

Parts of the country, including New Delhi and India's financial capital Mumbai, have imposed lockdowns with health facilities unable to cope with the latest wave of the virus.