Finish reading the article.
The test used to detect the virus are so sensitive that they can detect fragments of virus still present in the blood.
Those tested may have had the disease months ago.
They keep testing people that they haven’t tested before and detect people that no longer have the disease but have fragments in their blood.
The article also points out that since COVID is related to SARS and the common cold that false positives could be due to someone having the other viruses.
Having had the other viruses could also confer some immunity to COVID.
A helpful Freeper posted a link to an article recently that proposed that the actual mechanism that reduces viruses in summer is humidity and not temperature. I believe that summer in Saudi Arabia is probably very dry. Perhaps not the case in India; I don't know.
The paper I read used the word "sedimentation" to describe the idea that infectious droplets exhaled by an infected person could last longer in the air in less humid conditions. High humidity would preserve the size of exhaled droplets or possibly enlarge them. The larger, heavier droplets then settle quickly to the ground.
If low humidity causes droplets to decrease in size, this apparently allows them to stay suspended in the air for much longer and raises the chances of infecting a nearby person.
-How do they account for that?-
Human behavior. Its a variable that cannot be measured, controlled or even accurately observed. You can claim anything you want.