The increase in the number of deaths due to Covid-19 in Delhi might correlate with its poor air quality.
The daily death numbers have gone up quite high as November 18 witnessed 131 Covid-19 deaths in the capital. November has also been the most polluted month with fine particulate matter (PM2.5) in the air that is a concern for people's health.
It is quite interesting to observe that in June and July, the increase in the number of Covid deaths correlated with high positivity rate.
High positivity rate means the number of people turning positive out of the total number of people underwent Covid test.
For instance, on June 15, out of a total of 6,105 people who had undergone Covid-19 test, 1,647 reported positive. It shows a positivity rate of 27.38 per cent.
The pollution level was between the range of moderate and unhealthy around June and July.
However, in November despite a low positive rate, the number of deaths is quite high.
For instance, on November 18, out of total 62,232 people went through Covid-19 tests, 7486 came positive with a positivity rate of 12.03 per cent which is quite less as compared to the rate in June. But the number of death is 131.
This could be due to poor air quality because the PM 2.5 level has been between very unhealthy and hazardous since October.
PM 2.5 comes from sources such as agriculture burning, motor vehicles, power plant, etc. and once it enters the body through respiration, it affects the lungs and heart of a person.
Weekly data analysis makes sense as a patient generally loses the battel with Covid-19 at least a week or ten days after being tested positive.
Health and data experts say that though various other factors like more localised study can give a more conclusive answer yet the possibility of air pollution as a major factor for the increase in Covid-19 death cannot be ruled out.
Sapio Analytics co-founder and CEO Ashwin Srivastava says, "This is actually very interesting. Though determining cause and effect with a single data point is not possible, it does give a lot of perspective into the significance of the PM2.5 value, considering our ground research shows that the mortality rate is higher in areas where morbidity rate in lung diseases is higher and the direct correlation between lung diseases and high pollution level is well documented."
Srivastava adds, “There are well-researched stories by Harvard University and the University of Cambridge on the link between mortality rate and fine particulate matter.”
He agrees that in Delhi pollution clearly seems to be playing a role in increasing the cases of Covid-19 deaths, when the data is seen in the perspective of various research works establishing the linkage.
Dr Jugal Kishore, director, professor and head of the department, community medicine, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi says that prima facie there seems to be a co-relation of pollution and Covid-19 deaths. “It requires more in-depth research along with many other contributing factors,” Kishore said.
However, Dr (Prof) NN Mathur, Director, Lady Harding Medical College, finds fault with the testing strategy for low positivity rate."
The decrease in positivity rate in November could be due to an increase in tests with a significant proportion of them being Rapid antigen tests where many results come false negative. Therefore, the decrease in positivity rate in November could be a false finding,” Dr (Prof) Mathur said.
Data is unavailable on the government website from November 18 onwards.