Covid lockdown-level curbs could help clean Delhi’s air by 2040: Study

Between 2019 and 2025, the study said, despite several policy announcements, Delhi’s annual average pollution has largely hovered around 100 µg/m³ consistently.

The Capital can cut its national annual average load of particulate matter (PM) 2.5 to reach the national ambient standard by 2040 if it undertakes emissions curbs equivalent to the levels seen during the Covid-19 lockdown, a new working paper has found.

A layer of smog in the city during the early hours on Sunday. (Vipin Kumar/HT Photo)

Titled ‘40 by 2040: Cost of inaction and delays in reaching Delhi’s air quality target’, the study looked at Delhi’s PM2.5 concentrations across 36 years from 1989 to 2025. The analysis, carried out by air quality researchers Sarath Guttikunda and Sai Krishna Dammalapati from Urban Emissions, an environmental advocacy group, argues that a combination of up to 55% reduction from all anthropogenic sources, a 75% drop in winter heating emissions, and a 100% drop in stubble burning emissions can help the city reach national ambient standard of 40 µg/m³ set by the Central Pollution Control Board (CPCB).

Between 2019 and 2025, the study said, despite several policy announcements, the city’s annual average pollution has largely hovered around 100 µg/m³ consistently — 2.5 times the national standard and 20 times the World Health Organisation (WHO) guideline of 5 µg/m³.

It places the responsibility for this squarely on implementation delays rather than lack of scientific or policy knowledge. It notes that, if every action listed in the National Clean Air Programme’s 2019 clean air plan had been implemented as intended, Delhi could meet the national annual ambient standard by 2040 or even before that.

The authors quantify two financial and health risks: the cost of inaction and the cost of implementation delay. If Delhi only manages to reach 60 µg/m³ in 2040 instead of 40 µg/m³, the city will experience 11.6% more exposure cases than if the target were met. If the concentrations remain at 100 µg/m³, that number jumps to 35.3% more mortality cases for every 100 cases estimated under the 40 µg/m³ trajectory.

Exposure cases refer to the number of additional cases where the population is vulnerable to health impacts due to inaction.

The researchers also use the COVID-19 lockdown as a benchmark for what is technically possible, stating the two sectors that were unaffected during the lockdown restrictions were heating, which is a phenomenon limited to the winter months (and thus irrelevant during March, April, and May), and stubble burning of post-harvest agricultural residue, which also had very limited influence during those spring months.