Residents of India's capital experienced a slight reprieve in 2025, breathing the cleanest air the city has seen since 2020. However, this marginal improvement offers little comfort, as the air quality remained alarmingly toxic, far exceeding both national and global safety benchmarks.
A Glimmer of Improvement Amidst a Toxic Reality
Data analysed by the think tank EnviroCatalysts from the Central Pollution Control Board (CPCB) reveals a complex picture. The average concentration of deadly PM2.5 particles in 2025, calculated up to December 29, stood at 98 micrograms per cubic metre. While this marks a dip from previous years, it is a staggering 2.45 times higher than India's annual national standard of 40 micrograms per cubic metre. More critically, it is 19.6 times higher than the World Health Organization's (WHO) stringent safety guideline of just 5 micrograms per cubic metre.
The story is similar for larger PM10 particles. The annual average for 2025 reached 200 micrograms per cubic metre, which is 3.3 times the national standard of 60 and 13.33 times the WHO guideline of 15.
What Drove the Slight Improvement in 2025?
Experts attribute this year's marginal betterment to a fortunate combination of meteorological and man-made factors. These included above-average rainfall from May to October, an early Diwali celebration which may have condensed the period of firecracker pollution, a reduction in stubble burning fumes from neighbouring states, and the prevalence of strong winds on most days that helped disperse pollutants.
Looking at the five-year trend, Delhi's annual average PM2.5 levels were 104 micrograms per cubic metre in 2024, 101 in 2023, 99 in 2022, 107 in 2021, and 98 in 2020. This indicates that after rises in 2023 and 2024, levels have dipped back to the 2020 baseline. For PM10, the levels were 212 (2024), 207 (2023), 213 (2022), 215 (2021), and 190 (2020).
Locally, the most polluted hotspots in 2025 were Jahangirpuri (130 µg/m³ PM2.5), Wazirpur (124 µg/m³), and Anand Vihar (121 µg/m³).
Expert Warnings: Systemic Change is Non-Negotiable
Analysts caution against any premature celebration. Sunil Dahiya, founder and lead analyst of EnviroCatalysts, stated that the persistently high pollution levels, which are more than twice the national standards, indicate that the emission load in the wider airshed has long surpassed the region's environmental carrying capacity.
"While the stagnation of these levels over the past five to six years, despite rising population, consumption and industrial activity, indicates that emission intensity per unit of production may have improved, the overall increase in activity quickly offset those gains," Dahiya explained. "The fragmented nature of emission reduction efforts across sectors further limited progress."
Echoing the need for a comprehensive strategy, Anumita Roychowdhury, executive director for research and advocacy at the Centre for Science and Environment (CSE), emphasized the need for detailed reporting on systemic measures. "The critical takeaway is that, despite recent stabilisation, harmful PM2.5 levels remain several times higher than national standards," she said.
Roychowdhury concluded that "achieving compliance with both national standards and the more stringent WHO guidelines require accelerated implementation of an ambitious, near-zero emissions roadmap across all key sectors." The message is clear: without transformative, sector-wide action, Delhi's air will remain a severe public health crisis, regardless of temporary meteorological relief.
