First thing first. Coronavirus disease — COVID-19 — is not an opportunity. Let us call it what it is, a world-wide disaster, which isn’t just a health crisis, but also a livelihood and humanitarian crisis. The rich and the privileged should not need a disaster, like the present pandemic, to learn the ecological and health benefits of driving fewer cars and consuming less energy.

COVID-19 has brought the world to a grinding halt as almost all the countries are at present under a partial or a complete lockdown. This makes Earth Day 2020 a unique event when there are no annual ribbon cutting exercises before planting a sapling, or auditorium full of people vowing to protect “our blue and green planet, the Mother Earth”, year after year, while the earth hots up and climate change-related disasters are on the rise. This the climate scientists have been warning us for quite some time now.

India reported its first novel coronavirus case earlier this year on January 30. As of today, April 22, there are 15,474 active cases in the country (3,869 cured/discharged) with 640 reported deaths, as mentioned on the website of the Union Ministry of Health and Family Welfare.

On March 24 evening, the Prime Minister Narendra Modi declared a nationwide lockdown for 21 days to contain the spread of COVID-19. This has further been extended to May 3 with a set of revised guidelines that exempt certain activities and essential services.

With offices, educational institutes, shopping malls, markets, airports, railways, road transport, construction activities shut, our cities, choking on a cocktail of toxic air pollutants, have started to breathe. In the absence of haze, which had become a normal vision in urban India, images of blue skies are splashed all over Twitter and Instagram. Urban residents are unable to contain their excitement on being able to see a skyscraper 500 metres away from their home.

The air in our cities is much cleaner than it was before the lockdown. And there is data to show the drastic reduction in air pollution levels.

As part of the Earth Day, M Rajeevan, secretary, the Union Ministry of Earth Sciences delivered a web lecture on the ‘Earth’s response to COVID-19 pandemic’. He shared comparative data on air pollutants — particulate matter and other gaseous pollutants — in various Indian cities before and after the lockdown.

From the second week of March, when coronavirus cases started to rise in the country, mobility trends show a drastic reduction in walking and driving. There has been a reduction in retail and recreation trips, grocery trips, workplace and transit station trips, etc (see graphs: COVID-19 community mobility report).

“These changes in mobility trends due to the lockdown have had a direct impact on air pollution levels in the cities” said Rajeevan. “Not just particulate matter, such as PM10 and PM2.5, cities have also recorded a reduction in nitrogen dioxide, carbon monoxide and other gaseous pollutants,” he added. For instance, cities like Delhi, Pune, Ahmedabad, Chennai, Kolkata have shown a drastic percentage decrease in PM2.5 (see graph: Percentage decrease in PM2.5 due to the COVID-19 lockdown)

Graph: Percentage decrease in PM2.5 due to the COVID-19 lockdown (between March 21 and April 20, 2020)

Source: M Rajeevan 2020, Earth response to COVID-19 pandemic, Earth Day web lecture.

Delhi, which has the global ‘recognition’ of being one of the topmost cities with high air pollution levels, has also seen a drop in air pollutants in the last one month, as compared to the levels last year same time period (see graphs: Decrease in PM2.5 and NO2 in Delhi due to the COVID-19 lockdown).

Air pollution data averaged over 29 stations in Delhi, between March 25 (when the nationwide lockdown was announced) and April 19, shows a 57 per cent reduction in PM10 levels, 45 per cent reduction in PM2.5, 83 per cent reduction in nitrogen oxide (NO) and 65 per cent reduction in nitrogen dioxide (NO2).

“NO2 is an atmospheric pollutant emitted by combustion processes and has a short lifetime of less than one day… Significant decline is observed in NOx concentration because of restriction in fossil fuel burning sources in the lockdown,” explained Rajeevan.

The reduction in air pollution levels due to the lockdown is not limited to Indian cities alone. There has been a significant decline in NO2 density in the cities of China and the US (see map: Changes in mean tropospheric NO2 density in cities of China between January and February 2020).

Map: Changes in mean tropospheric NO2 density in cities of China between January and February 2020.

Source: M Rajeevan 2020, Earth response to COVID-19 pandemic, Earth Day web lecture.

Clearly, what the climate scientists and public health experts have failed to drill into our heads (read common sense to reduce emissions and breathe cleaner air), novel coronavirus, with a diameter of approximately 60–140 nanometre (a nanometre is one billionth of a metre) has forced upon us.

While our cities have cleaner air and fishes have returned to our water bodies, COVID-19 is too heavy a price to pay to clean up the planet.

Remember while we are locked up inside our homes with stocked up food supplies, it is the poor and the marginalised who are out in the heat and amid the threat of coronavirus, either locked up in migrant shelters, or standing in kilometre long queues to collect food packets. Many have collapsed and died while walking hundreds of kilometre in the hope of reaching their homes. Daily wagers have lost their livelihoods and have no social security. Like in most disasters, the poor are disproportionately affected by COVID-19, too.

Researchers are linking novel coronavirus with deforestation, and scientists are warning deforestation and climate change together could unleash “a mind-boggling number of coronaviruses”.

Clearly, it is no rocket science to understand what needs to be done to avoid future pandemics, which, in the present world order, seem imminent.