The country has been witnessing rapidly evolving dynamics on multiple fronts in recent weeks. While much of the public discourse has been dominated by Election Commission-related developments, it was particularly gratifying to hear a minister in Delhi make a scientifically important observation: “PM₁₀ does not travel as far as PM₂.₅, so the construction contributes far less to pollution than vehicular emissions.” This is the kind of scientific understanding I have long wished to hear from policymakers and authorities. Nearly a decade ago, while presenting the SAFAR (System of Air Quality and Weather Forecasting and Research, India’s first air-quality forecasting framework) findings under the MoES, I reported that the transport sector was a major contributor to Delhi’s toxic pollution, accounting for around 40 per cent of PM₂.₅ emissions. At the time, the finding was uncomfortable. It provoked strong resistance, even a backlash. Although it was clear that PM2.5 was the most harmful to our health, we continued to devote disproportionate attention and resources to the second- or third-tier contributors, especially dust, because the National Clean Air Programme (NCAP)’s metric gauges funding, assessing performance and mitigation progress by percentage reduction in PM₁₀, where dust is a major contributor. This inevitably shaped pollution-control priorities. It is encouraging to see scientific understanding of Delhi’s pollution sources gradually finding greater acceptance in policy........

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