Delhi, Dec 25: For residents of Delhi, breathing freely has become increasingly challenging. While air pollution discussions often focus on Particulate Matter (PM2.5), this winter, Nitrogen Dioxide (NO2) has emerged as a major threat. Recent data shows that NO2 levels in the city have reached their highest point in seven years, primarily due to vehicular emissions, fossil fuel burning, and stagnant winter weather conditions, according to a report by the Times of India.
A Seven-Year High
Analysis of Central Pollution Control Board (CPCB) data by think tank EnviroCatalyst reveals that Delhi’s annual average NO2 concentration has climbed to 47 micrograms per cubic metre (µg/m³) as of late December 2024. This marks a sharp rise from 43 µg/m³ last year, the highest level recorded since 2018, and nearly five times above the World Health Organization’s (WHO) safe limit of 10 µg/m³.
Primary Sources of Pollution
NO2 is a reactive gas produced during high-temperature combustion. In urban Delhi, traffic emissions are the leading source, followed by power plants, industries, and localized waste burning. Pollution hotspots include the ITO intersection, Terminal 3 of IGI Airport, Anand Vihar, and Shadipur, where morning and evening traffic surges trap the gas near the ground due to the shallow winter boundary layer. At ITO, NO2 levels averaged 69 µg/m³, the highest in the city.
Health and Environmental Impact
Breathing NO2 poses serious health risks. It irritates the airways, worsening conditions such as asthma and chronic obstructive pulmonary disease (COPD). Beyond human health, NO2 contributes to ground-level ozone formation and reacts with other pollutants to create secondary particulate matter, worsening overall air quality.
Addressing the Crisis
Experts stress that the NO2 spike is a local problem, unlike stubble burning, which has regional origins. Controlling the pollutant requires effective traffic management, enhanced public transport, strict enforcement of waste burning bans, and a shift from fossil-fuel dependent vehicles. Without urgent interventions, Delhi’s air will remain a silent but persistent threat to millions of residents.