From a “flu-like” disease to a global pandemic, the speed with which Covid-19 has spread has stopped the world from turning for an indefinite amount of time. However with factories shut, thousands of airplanes grounded, and city roads eerily free of traffic, the lockdown has helped air quality levels improve drastically over the past month.

The effect is so pronounced that its not just the pollution monitors around the world, but meme-makers — frontline workers of pop culture — also picked up on it.

And while the Coronavirus pandemic is a global health emergency, we at Blue Sky Analytics monitor and quantify the issues of climate change, such as air pollution and carbon emissions. This is why we decided to further study these observations and see the extent of the drop in pollution levels in India through our award-winning data analysis which combines satellite data with on-ground monitors.‍

A Case Study of India’s Emission Levels

In this article we did a graphical analysis for the states of Delhi, Maharashtra, West Bengal, and Tamil Nadu, thereby covering north-south east-west points of the country and key economic hubs from each zone. For satellite imagery, we are using highly sophisticated measurements from Sentinel 5P for Nitrogen Dioxide (NO2) emissions and ECMWF CAMS for PM 2.5 levels. High-resolution satellite data along with on-ground data from government air quality measuring devices known as BAMS allows our AI-powered algorithms to accurately analyze air quality for an entire region.

This combined power of AI/ML and geospatial data allows us to develop a holistic comparison of 3 months (January to March) in 2019 versus 2020 for entire states. This provides a more realistic view of emission levels as we are not limited by the location on-ground sensors, which tend to be concentrated in urban areas and not so much in industrial towns and villages.

The main sources for PM2.5 are industrial emissions, construction work, and waste burning; and the main sources of NO2 are industrial output and vehicular emissions. Both are highly indicative of economic activity in the region.

Post the national lockdown announcement on March 21, a significant reduction and downward trend in NO2 and PM2.5 levels have been observed in all chosen states. In general, we start seeing a decline in air pollution mid-January onwards due to increase in temperature and wind speed and during the transition from winters to spring (pollution is significantly influenced by weather conditions like humidity and wind speed and these can never be eliminated as possible reasons for the decline. However, regions broadly have similar weather conditions in the same months of successive years).

However, in 2020 there was a substantial decline in economic activity and travel due to the beginning of economic recession and the onset of Covid-19. Hence, even prior to the lockdown date the emission levels had started declining in 2020 as compared to 2019. We now present our graphs followed by analysis. There are a few points to note as you at home, read these graphs as well:

  1. The faded line represents pollutant level in 2019 and the darker line represents pollutant level in 2020
  2. The green portion highlights when India was under a nationwide lockdown.
  3. The scale on the y-axis is different for different pollutants/states. Avoid being misled by this when a more polluting state shows a downward trend and a less polluting state shows an upward trend.


In Delhi, we can see a very clear trend where the NO2, PM2.5 levels dropped visibly in 2020, and even more so during the national lockdown.

Delhi is known for its smog and dangerously high air pollution in winter months. As the temperature rises in February and the stubble burning from nearby agricultural centers comes to a halt, we see improvement in Delhi skies; however, they are still well above safety limits. In the lockdown period, the city has experienced ‘Good’ to ‘Moderate’ air for the first time in years.

The capital to a country of 1.3 billion people, it has coal power-plants, high vehicular emissions and unfavorable geography which are some key factors responsible for the alarming air quality


In Maharashtra too, we see a steep decline in the emissions level of PM 2.5, SO2 and CO emissions during the lock down period.

A coastal state and industrial hub, its proximity to the sea usually keeps its particulate matter levels low, however it is susceptible to high levels of SOx and NOx content in the air due to vehicular pollution, industrial production and power plants.

Maharashtra is also the worst hit state in India by Covid-19

West Bengal

For West Bengal, we have limited our presentation to PM2.5 levels due to inconsistencies in data sources. Here we again see a visible difference between 2019 and 2020 in PM2.5 levels during the end of March. Generally, the period between January and March 2020 saw lower PM2.5 levels than in 2019.

Tamil Nadu

In Tamil Nadu too the trend of drop in NO2 and PM2.5 levels in 2020 continues. Since the lockdown, we can see a steeper decline. Tamil Nadu is also one of the hardest-hit states by the Covid-19 pandemic, the effects of which can be clearly seen through a decline in economic activity.

An Unexpected Case of Collective Activism?

It is evident across the states that there has been a significant decline in emission levels since most humanity sequestered itself indoors. This sort of collective action on a global scale, though accidental, has shown us that reversing climate change is possible if we reduce our usage of fossil fuels to power our lives — a fact that big oil lobbyists have spent millions trying to obfuscate.

Over the last two decades, organized climate change denial funded by oil companies and peddled by politicians has followed a playbook of denial and downplaying the urgency of the situation. However, in the past few years, the adverse effects of climate change have become undeniable. We can see with our own eyes the extremely bad smog that blankets our cities all year round, how rainfall-related floods are becoming more extreme, unprecedented forest fires, and super-strong hurricanes.

In face of undeniable proof of climate change and mounting evidence linking human activities to it, fossil fuel industrial complex is finding innovative ways to ensure that the world continues to use crude oil, natural gas, and coal to power itself. According to a report by data platform Statista in 2019 companies like BP, Shell, ExxonMobil, and Total spent over $200 million in lobbying and engage politicians and the public. The report states that this lobbying involves controlling, delaying, or blocking climate-related policy.

The new form of climate change denial maintains that every country should be left alone to do as they see fit. That greenhouse emissions are individual responsibility. That collective activism is useless. That there is no rush to deal with climate change.

The Covid-19 pandemic and the lockdowns due to it have given undeniable proof to the people that it is our fossil fuel-run lifestyle that plays havoc with the planet’s climate. Though this grinding halt to the world economy and normal life is not a sustainable way to cut down on emissions, this brief respite from the toxic air of our cities does show how fast we can reduce our usage of fossil fuels.