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Today, as mankind is fighting a battle with the COVID-19 pandemic and India fights a double battle of ‘reverse migration’, there is heartening news as well. Covid-19 has caused more than 2.6 billion people worldwide and their economies to plunge into a lockdown, with an intensity greater than even the Second World War. In most countries, traffic and economic activities have come to a standstill. This crisis however, presents a unique opportunity to view our environmental goals. And less polluted air is its direct outcome.
International traffic and air quality situation
Images released by the European Space Agency’s (ESA) Copernicus Sentinel-5P, show a massive reduction in air pollution levels across all European cities during this time. Nitrogen oxide (NO2) concentrations; produced by vehicles, power plants and heavy industries, in large cities such as Paris, Milan and Madrid have reduced significantly. According to GPS maker TomTom, the percentage of roads congested with traffic in London on March 26, dropped from 71 per cent in 2019 to just 15 per cent in 2020. Air pollutant concentrations in Rome and Milan also dropped by over 50 per cent.
A video shared by ESA, shows a visible drop in NO2 concentrations in late January 2020 over China, coinciding with the nationwide quarantine. “We can certainly attribute a part of the nitrogen dioxide concentration reduction to the impact of the coronavirus”, said Claus Zehner, ESA’s Copernicus Sentinel-5P mission manager. There is also a significant decrease in fine particles (PM 2.5). Fine particulate matter is a mixture of solid particles and small liquid droplets. Activities like transportation, construction sites, farms, fire are its main sources.
India’s air quality better than it has been for decades
Similar drop in pollution levels were also recorded in India, after countrywide lockdown was announced by the Prime Minister on March 24, 2020. Lives of over 1.3 billion people virtually came to a standstill in an effort to save themselves from the spreading virus. Both the NO2 and PM 2.5 level dropped significantly across Indian cities.
According to the System of Air Quality and Weather Forecasting and Research (SAFAR), PM 2.5 level reduced by 30 per cent in Delhi and 15 per cent in Pune in March 2020 with respect to 2018-19. The average AQI now seen in Delhi has never been achieved till date and the air quality index launched in 2014 has never seen lower measurements.
A great reduction was visible in NO pollution level, which is largely caused by motor vehicles. Due to COVID 19 control measures, NO2 reduced by 43 per cent in Pune, 38 per cent in Mumbai and 50 per cent in Ahmedabad. Although rainfall also played a part in pollution control measures, yet the impact of COVID-19 is visible.
A comparison of Delhi’s very polluted Anand Vihar shows a stark contrast between pre and post lockdown periods. The Air Quality Index (AQI) data shows that the average PM 2.5 level at the location on March 29, 2020 was 46 which is a ‘satisfactory’ green, comparable to any European city. Just three months back on December 29, 2019 (Fig. 1), the PM2.5 level at the very place was 451, a severe category. In AQI, the PM2.5 level of 0 to 50 is considered good, 51 to 100 a satisfactory level, while a level of 401 to 501 is considered severe and detrimental to human health.
Before and After: The drastic change in Delhi’s air quality goes to show the impact of anthropogenic activities on a city’s climate. The Delhi government should see this as a silver lining and design effective solutions post the lockdown.
Some scientists, however, believe that lockdown will not reduce all types of pollution. Dr Eiko Nemitz, from the UK Centre for Ecology and Hydrology, says that reduction in traffic and industrial activity have reduced pollution levels, but as more people are living in their homes now, pollution from domestic sources would continue. This will also give rise to issues of indoor pollution.
The global environmental data however provides important variables that scientists can now use for modeling. The satellite images and air quality indexes decidedly show that lesser human activities ensure clean surroundings around the globe. Last but not the least, COVID-19 has not only exposed the inherent bottleneck in the strong health infrastructures of so called developed countries, but it also proved those scientists right who were calling to restrict pollution caused solely by unrestrained human activities.
- Tracy, 2020. GPS World-Analysis of satellite imagery shows reduced NO2 in China, Italy.
- SAFAR-India-Impact of COVID-19 control measures on air quality.
- World Health Organisaiton- Zoonoses disease.
- Delhi Air Pollution: Real-time Air Quality Index
- Morrison Ryan- Mail Online, Satellite images show massive reductions in air pollution over Paris, Madrid and Milan following lockdown measures to slow the spread of the deadly coronavirus in Europe.
- Emily Beament and Shivali Best-Mirror, Air pollution halved in London, Rome and Milan as cities go into coronavirus lockdown.