Delhi's Air Quality Emergency: Expert Advice from Prof S N Tripathi on Why the City is Stuck in a Pollution Loop

Delhi's air quality has become a serious concern, drawing attention for its alarming deterioration. The dense fog settling over the city and its surrounding areas is more than just a weather phenomenon; it's a critical environmental concern, contributing to the persistent smog that traps pollutants and affects millions of lives. Here's an in-depth look at the science behind this issue and the dire situation unfolding in the capital.

Delhi's Smog Crisis: Prof. Tripathi's Insights

Fog, a condensed form of water vapor, plays a significant role in creating smog. When pollutants accumulate near the earth's surface under calm wind conditions, they fail to disperse, becoming trapped in the dense fog. This phenomenon, combined with high humidity and stagnant air, results in prolonged exposure to pollutants.

Speaking to Climate Trends, an environmental organization in Delhi, Professor S.N. Tripathi, Dean of the Kotak School of Sustainability at IIT Kanpur, said, how this process becomes a vicious cycle. As particulate matter (PM) interacts with fog, it undergoes a chemical transformation, becoming more oxidized. The oxidized PM acts as condensation nuclei, making it easier for fog to form the next day. This cycle continues, intensifying smog conditions and prolonging periods of poor air quality.

Winter brings cold temperatures and high humidity, creating the perfect conditions for smog formation. With minimal wind to disperse pollutants, the air quality deteriorates further. Smaller fog droplets oxidize particulate matter faster, making subsequent fog formation easier and trapping pollutants for longer durations. This explains why consecutive days of severe air quality persist in regions like Delhi during winter.

After a week of "severe" air pollution, Delhi's air quality showed slight improvement but remained "very poor." On Thursday morning, the city recorded its lowest temperature of the season at 10.2°C, 2.1°C below average, with an Air Quality Index (AQI) of 376.

Sunday: AQI entered the "severe" category, leading to the imposition of GRAP-IV measures.

Monday & Tuesday: Air quality worsened to "severe plus," with AQI exceeding 450.

Wednesday: A slight improvement brought AQI back to "severe," but conditions remained hazardous.

Central Pollution Control Board (CPCB) defines AQI categories as:

Good (0-50)
Satisfactory (51-100)
Moderate (101-200)
Poor (201-300)
Very Poor (301-400)
Severe (401-500)

What Lies Ahead for Delhi-NCR?

The India Meteorological Department (IMD) predicts shallow fog during the day, with a maximum temperature around 27°C and humidity at 80%. However, experts warn that Delhi-NCR's air quality is likely to remain in the "severe" category until November 22, with only slight improvement afterward. For the next week, the air quality is expected to oscillate between "severe" and "very poor."

Addressing Delhi's smog crisis requires a multi-pronged approach:

Policy Interventions: Stringent measures to regulate industrial emissions, vehicular pollution, and construction dust.

Public Awareness: Encouraging citizens to adopt eco-friendly practices like carpooling and reducing outdoor activities during high-pollution periods.

Technological Solutions: Innovations in air filtration and real-time monitoring of pollution hotspots.

Delhi's battle with smog highlights the need for everyone to act against pollution. From stricter rules to small personal efforts, every step matters. As winter sets in, the city faces tough days, but smarter choices and sustainable habits can lead to cleaner air.