But the Indian Institute of Tropical Meteorology ’s (IITM) new measurements cannot yet say where a large share of the pollution they measure comes from, and its air pollution prediction model still runs on a 2021 emissions estimate that its own website says needs updating, with a replacement expected only by June next year. The Capital has its first breakdown of air pollution by source in nearly three years.
A second problem was that the lab’s total PM2.5 reading was itself far below what Delhi ’s monitors recorded. For instance, it was 55.3 micrograms per cubic metre (µg/m³) on October 22. That number was 47% of a middle reading of 117.1 µg/m³ among 37 stations that day, a comparison with Central Pollution Control Board (CPCB) air quality data from that day showed. The lab’s 25 instruments, for atmospheric chemistry, source apportionment (working out how much pollution comes from each source) and aerosol toxicity, cost about ₹ 80 crore. Delhi’s previous source studies, by IIT Kanpur in 2016 and The Energy and Resources Institute in 2018, are dated.
When this was pointed out by HT, officials said the site was still new and facing teething issues. “The PM 2.5 data will reflect accurately, shortly,” an official said. “This facility will help us understand the composition of pollution as well as the contribution of different sources,” said Union minister of state for science and technology Jitendra Singh, while inaugurating the lab, called the Advanced Atmospheric Chemistry and Aerosol Toxicity Analysis Laboratory (Aatal) at New Rajendra Nagar, on Saturday. He added that this was important for “ensuring that action is based on scientific evidence”. The model’s 2021 emissions inventory, its estimate of what each source releases, was “compiled using surveys done in 2016”, according to a 2024 paper by IITM scientists, and a replacement with a 2026 baseline is due only by June 2027. The Delhi government stopped a Washington University study in 2021 over “unsatisfactory” results and halted IIT Kanpur’s real-time study in November 2023, again dissatisfied with its methods and results.
