It's the time of the year again when you closely monitor the AQI apps on your phones and smell that burnt soot in the air.

The news landscape is buzzing with daily reports of worrying air pollution levels in the Delhi-NCR region as stubble burning begins in the neighbouring areas and economic life resumes post the lockdown. Complaints of low visibility, increasing breathing difficulties and exasperated allergies as a result of the 'poor’, ‘very poor’ and even ‘hazardous’ AQIs in metropolitan cities have started surfacing already - a trend that is observed every single year around the same time - even as state administrations and residents engage in policies and practices to mitigate the effects.

But this year, there is more.

Doctors, environmentalists and climate experts have exhaustively been advocating the dangers posed by the dual public health emergencies to human life. FIT speaks to pulmonologists to understand how air pollution is expected to intensify our COVID-19 fight and increase our likelihood to fall sicker with far higher risks of complications.

Preliminary research and isolated studies from different parts of the world have signalled a proportionate relationship between polluted air and COVID severity. Most notable is an ecological study from Harvard University, which found that even a small increase in PM2.5 levels was associated with an 8% increase in COVID-19-related deaths.

While the research is yet to be peer-reviewed, the findings are significant in highlighting the need to work towards measures to control air pollution and prevent the accompanying health hazards.

Other studies have also looked at the correlation between pollution and more COVID-related deaths. For instance, an analysis of COVID fatalities in Italy, Spain, France and Germany concluded that 78% of the deaths were in regions with the highest NO2 concentrations, combined with lower wind flow that prevented dispersion of pollutants.

It is also being investigated if air pollution can facilitate the spread of the novel coronavirus and lead to a spike in cases. While there is no direct proof of such a relationship, early evidence from Northern Italy suggests that the virus could be found on particulate matter, indicating that it may attach itself to airborne pollutant particles.

Nevertheless, more research is needed into this area to make conclusive statements, experts have said.

To put it simply, air pollution damages various parts of the body by infiltrating the blood vessels, causing inflammation and suppressing immunity. Large-scale evidence exists to support its contribution to heart diseases, stroke, diabetes, asthma, cancer and other comorbidities - all of which are known to increase complications in COVID-19 patients.

Speaking to FIT, Dr Nikhil Modi, senior consultant, respiratory, critical care and sleep disorder at Indraprastha Apollo Hospitals, explains that pollution becomes a grave concern because of the way it compromises the respiratory system and causes damage to the lungs, the prime target of respiratory infections such as COVID-19.

“Pollution, as we know, is akin to smoking. When we inhale the polluted air, it causes congestion in our chest and hampers the mechanism by which our airways or breathing tubes clear dust particles, viruses and bacteria from the lungs. When this is damaged, the chances of the virus staying there, going into the chest and causing symptoms will be high”, he says.

Research unrelated to COVID has also found that prior exposure to air pollution prolongs the duration of ventilation in intensive care patients.

In essence, air pollution is directly linked to several conditions and comorbidities that are known to increase COVID-19 complications and death risk. The adverse impact it can have on the immune system and the ways it can lead to inflammation, are all well-documented.

Not just this, pollutants in the air naturally cause congestion and coughing, assisting the transmission of the virus from a COVID-infected person - since it is known to majorly spread via respiratory droplets.

“Therefore, pollution could increase susceptibility to COVID in the first place, and then also increase the chance of a severe infection,” Dr Modi adds.

In an interview with India Today, Dr Randeep Guleria, Director, AIIMS, New Delhi, reiterated similar concerns. “Since there is a rise in air pollution, there is data to state through certain modelling studies from China and Italy (Europe) which show that in areas where there is even a little bit of increase in PM 2.5 levels, it leads to a surge of at least 8-9% in coronavirus cases.”

“Air pollution causes inflammation in the lungs and SARS-COV-2 also predominantly affects the lungs causing inflammation. It is likely that there could be severe infections during such time especially in the Indo-Gangetic plains where the pollution levels are higher,’ said Dr Guleria.

As FIT had reported earlier, a spike in COVID-19 cases can be expected as temperatures fall in the coming few months, as is observed with other coronaviruses and viral infections during winters.

But how does air pollution complicate matters further?

Dr Vikas Maurya, Director and Head of Department, Pulmonology, Fortis Hospital Shalimar Bagh, Delhi, explains, “The winter season coincides with high pollution due to more concentration of particles in the air. This is also part of the reason why every year, we see a surge in respiratory viral infections during this time. This trend is nothing new, but with COVID-19, the challenge has, of course, increased manifold.”

Professor Francesca Dominici, who led the Harvard Study, told the Guardian, “Air pollution is not yet getting enough attention because of the slow peer-review process (for academic studies). But hopefully, as this and other studies are published, the topic will get more attention and most importantly will affect policy.”

While the challenges and risks are set to multiply due to the deteriorating air and change in temperature, the solutions remain the same. Masks, distancing and respiratory hygiene can help prevent COVID-19 and cut down its transmission rate. On the other hand, targeting air pollution on a personal as well as policy level would be required to decrease the risk of complications from COVID and other illnesses. What this does mean, eventually, is that battling the pandemic involves layers of redressal and cannot occur in isolation.