NEW DELHI: As the second wave of Covid-19 continues to recede in all states of the country, a curious north-south divide has emerged in the falling trends.
In most states of northern India, cases have been declining in double quick time, literally, as compared with Maharashtra and the southern states.
Since hitting its peak on May 9, the seven-day rolling average of daily cases in Haryana has declined at an average rate of 8.9% each day (till June 3), the sharpest among 18 major states that TOI looked at.
The decline has been almost as dramatic in Rajasthan (8.5%), Delhi (8.2%), Bihar (8.1%), Uttar Pradesh (7.8%) and Uttarakhand (7.6%).
In Maharashtra and across the south, the fall has been much more gradual, ranging from 2.7% in Tamil Nadu to 4.2% in Andhra Pradesh.
This means that in most states of north India, cases have been falling at more than twice the rate of decline seen in the south and Maharashtra.
For each state, the rate of fall was calculated from the time the seven-day average of daily cases hit its peak.
Nationally, cases have fallen at a daily average of 3.7% since hitting a peak on May 8.
The difference between the rates of decline in north and south India is too stark for it to be just a statistical quirk.
Experts pointed to the leakier Covid reporting systems in the north as one possible reason for the divide.
“One needs to ask, how good are the reporting systems in the states showing a sharp fall in cases,” virologist Gagandeep Kang told TOI when asked for possible factors behind the north-south divergence.
“Certainly, the states that have a relatively better healthcare system, like those in the south, are expected to have good reporting,” she added.
Kang also pointed to two other factors, some or all of which could have a role in explaining the difference.
“It is possible that different variants of the virus could be in circulation in different regions.
Also, prior exposure to the virus that would determine the seropositivity among different populations needs to be looked at,” the expert said.
The difference in the rates of decline in cases can be understood better by looking at two states with comparable sizes and dates of reaching the peak — Maharashtra and Uttar Pradesh.
The second wave ravaged both states with Maharashtra touching a high of 65,447 cases (seven-day average) on April 24.
UP reached its peak around the same time, 35,010, on April 27.
Yet, Maharashtra reported an average of just over 17,000 cases on June 3 while the corresponding number in UP had dropped to 1,742.
The daily rate of fall in the northern state, at -7.8%, was twice as sharp as the rate seen in Maharashtra (-3.3%).
As a result of this general trend, the relative share of Maharashtra and the southern states put together in the daily national count has risen to over 70%, from less than 50% at the peak of the second wave in the country.
States in east India have shown a relatively low rate of decline.
Daily cases have been falling at 3.4% in Bengal and by 4.1% in Odisha.