Of course it is each, both, and the push and pull in between. It will be months or years before we can accurately deconstruct the interplay and proportions behind the exponential surge in disease and death across the subcontinent.
More contagious variants are implicated. Some of these variants may be innately more lethal. It is also possible that as demand for healthcare overwhelms supply, more people die because quality of care declines.
The explosion of confirmed daily cases — about 80,000 per day on April 1 to over 400,000 today (both undercounts) — provides the virus a very fertile evolutionary seed-bed. This is a threat to all of us, even those already vaccinated on the other side of the planet.
The virus seeks to thrive. Many people make choices that are expeditious for the virus. The virus has a biology adept at exploiting behavior that facilitates viral density and circulation. This is why crowds are a problem and interior crowding is an especially bad choice.
Many more us need to make choices that contain and slow the virus.