Gas and firewood furnaces at a crematorium in the western Indian state of Gujarat have been running so long without a break during the COVID-19 pandemic that metal parts have begun to melt.

"We are working around the clock at 100% capacity to cremate bodies on time," said Kamlesh Sailor, the president of the trust that runs the crematorium in the diamond-polishing city of Surat.

And with hospitals full and oxygen and medicines in short supply in an already creaky health system, several major cities are reporting far larger numbers of cremations and burials under coronavirus protocols than official COVID-19 death tolls, according to crematorium and cemetery workers, media reports and a review of government data.