A comprehensive ten-year evaluation has delivered a sobering verdict on the air we breathe, revealing that not a single major Indian city managed to achieve 'good' air quality standards at any point between 2015 and November 2025. The analysis, which scrutinized long-term pollution trends, underscores a persistent national public health crisis.
Delhi's Persistent Reign as Pollution Capital
The report, prepared by the environmental research firm Climate Trends, analyzed data from 11 major urban centers. It found that Delhi consistently remained India's most polluted metropolis throughout the entire decade. The city's average Air Quality Index (AQI) levels peaked dramatically, soaring above 250 in 2016. Although there have been marginal improvements since 2019, with current levels hovering around 180, the national capital has never come close to meeting healthy air-quality thresholds.
This chronic pollution is driven by a combination of factors. Vehicular emissions, industrial pollution, and crop burning are identified as the primary contributors. These sources are further intensified by the region's challenging geography, which traps pollutants and prevents their dispersal.
A Widespread National Crisis with Glimmers of Change
The problem is far from confined to Delhi. Other northern cities, including Lucknow, Varanasi, and Ahmedabad, recorded persistently high average AQI values, frequently exceeding 200 during the first half of the decade under review. However, the report notes that these cities demonstrated some improvement in the latter five-year period.
Meanwhile, cities in the south and west, such as Mumbai, Chennai, Pune, and Bengaluru, fared relatively better, registering what the report terms 'moderate' AQI levels. Despite this, they still failed to meet the safe air quality benchmarks. Notably, Bengaluru posted the lowest AQI readings in the country, ranging between 65 and 90. While this is the best performance nationally, it is still too high to be classified in the 'good' category. The AQI is calculated based on the concentration of hazardous particulate matter, specifically PM2.5 or PM10, whichever registers a higher value.
The Inescapable Role of Geography and Weather
Experts emphasize that geography plays a pivotal role in prolonging dangerous pollution episodes, particularly across the northern plains. Mahesh Palawat, Vice-President at Skymet Weather, explained the current meteorological challenges. "With cold north-westerly winds sweeping into the plains, minimum temperatures are set to drop further—making it even harder for pollutants to disperse," he stated.
Palawat added that this year's western disturbances were weak and inadequate, failing to trigger the widespread rainfall needed to cleanse the atmosphere. "Without rain to wash pollutants out, the pollution lingers for longer periods, leading to early and persistent smog-like conditions," he said. During the cold winters of the Indo-Gangetic plains, a phenomenon known as 'temperature inversion' effectively traps pollution close to the ground by limiting vertical air movement. This natural lid is worsened by dense urban structures and tall buildings that further slow wind speeds, exacerbating the stagnation.
The Urgent Call for Data-Driven Policy Reform
In light of these findings, experts are unanimously calling for smarter, science-based interventions. Professor S N Tripathi of IIT-Kanpur highlighted the importance of reliable information, stating, "Technology can help address many local pollution sources within your own airshed, but this requires reliable data."
Echoing the need for decisive action, Palak Balyan, research lead at Climate Trends, concluded, "What India needs is sustained, long-term, science-based policy reform backed by genuine political will to take tough decisions." The decade-long data makes it clear that without such concerted effort, clean air will remain a distant dream for India's urban millions.
