Lauri Myllyvirta and Sunil Dahiya
The nationwide one-day curfew in India last Sunday (Mar 22) resulted in the lowest average level of nitrogen dioxide pollution ever recorded in the spring season, in urban areas with monitoring. Other dangerous pollutants, PM2.5 and PM10, also dropped steeply but didn’t break records. These pollutants have much longer atmospheric lifetimes and cars are a much smaller contributor to their levels.
The COVID-19 crisis is resulting in widespread human suffering around the world. Air pollution levels are plummeting in many countries as an unintended result of measures against the virus; this should not be seen as a “silver lining”, but it does show how normalized the massive death toll from air pollution has become. Once the COVID-19 crisis is over, there are far more effective ways for governments to address air pollution than shutting down large parts of the economy, such as enforcing emissions standards for large polluters.
NO2 is a dangerous pollutant, responsible for an estimated 350,000 new cases of child asthma and 16,000 premature deaths per year in India. It is also a key contributor to PM2.5 formation.
While air pollution levels in individual cities can vary a lot depending on weather conditions, national-average levels across a landmass of thousands of kilometers are less affected by the vagaries of winds and rains. The national average levels do drop lower in the summer, when average wind speeds are higher and there is more atmospheric mixing, but last Sunday’s reading is the lowest seasonally-adjusted level on record.
Pollution levels in India have been trending down noticeably since the economy started to cool down in early 2019. We highlighted the slowdown in emissions in this article, posted six months ago.
What’s noticeable is that the fall in pollution levels is not led by the largest metropolises, where the pollution grabs most attention from policymakers and media. This indicates that the fall in pollution levels is driven by broader economic factors more than air quality policies, which currently are highly localized. To avoid pollution levels bouncing back as the economy turns a corner and the coronavirus crisis passes, a shift from the current highly fossil fuel dependent economy to clean energy based systems has to be adopted.
Methodology note: the data includes all stations that reported real-time data since the beginning of 2019, to enable year-on-year comparisons. National averages are averages of all cities with data, not weighted by population or number of stations. The 12 cities chosen for city-specific data are the ones with the largest number of stations.
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