 "What is Air Quality Index (AQI)")
Air Quality Index
What is Air Quality Index (AQI)
The air quality index (AQI) is an index for reporting air quality on a daily basis. It is a measure of how air pollution affects one's health within a short time period. The purpose of the AQI is to help people know how the local air quality impacts their health. The Environmental Protection Agency (EPA) calculates the AQI for five major air pollutants, for which national air quality standards have been established to safeguard public health.
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Latest Updates on Air Quality Index
Delhi AQI improves slightly to 164, pollution from fine particles persists
PM2.5 and PM10 remained the dominant pollutants, though readings varied across monitoring stations
 "Delhi AQI improves slightly to 164, pollution from fine particles persists")
Delhi records best AQI for Oct 24 in 10 years excluding Covid period: Govt
According to a statement issued by the Environment Department, the AQI stood at 306 on October 24 in 2024 and 275 on the corresponding date in 2025, before declining to 191 this year
 "Delhi records best AQI for Oct 24 in 10 years excluding Covid period: Govt")
Delhi AQI improves slightly to 223; poor air quality likely through Sunday
Delhi witnessed its first 'poor' air quality day of the season on Wednesday, earlier this week. According to weather agencies, the poor air quality is likely to persist until October 25
 "Delhi AQI improves slightly to 223; poor air quality likely through Sunday")
Best of Opinion: Will El Niño's delayed fallout show up in H2FY27?
Today's editorials and columns examine SBI's cybersecurity concerns, Delhi's pollution response, El Niño's impact on economic growth, EU steel regulations and India's electric vehicle transition.
 "Best of Opinion: Will El Niño's delayed fallout show up in H2FY27?")
Delhi wakes up to poor AQI at 226, Grap-I restrictions in force across NCR
While the national capital's overall AQI stood at 226 at 7 am on Thursday, some areas of Delhi recorded very poor air quality
 "Delhi wakes up to poor AQI at 226, Grap-I restrictions in force across NCR")
Grap Stage 1 invoked across Delhi-NCR as AQI enters 'poor' category
Grap Stage 1 measures include mechanised road sweeping, water sprinkling to control dust, regular waste collection and action against open waste burning
Delhi's air quality slips to poor category, forecast to worsen further
Delhi's AQI reached 219 at 7 am on Wednesday, with forecasts indicating poor air quality over the coming days
 "Delhi's air quality slips to poor category, forecast to worsen further")
Govt plans to roll out BS-VII emission norms in 3 phases from April 2029
The proposed BS-VII norms aim to cut emissions across pollutants by 20-50 per cent, with stricter limits on vehicle emissions under real-world driving conditions
 "Govt plans to roll out BS-VII emission norms in 3 phases from April 2029")
Delhi logs lowest September average AQI in 5 years as air quality improves
Delhi's monthly average AQI stood at 102 in September, while January-September saw 194 days with an AQI below 200, the highest number in the past five years
 "Delhi logs lowest September average AQI in 5 years as air quality improves")
IMD predicts heavy rainfall across most states; Delhi may get light showers
Maximum temperature likely to remain between 38 and 40 degrees Celsius in Delhi; heavy rainfall alert continues over parts of eastern and northeastern India
 "IMD predicts heavy rainfall across most states; Delhi may get light showers")
Cloudy skies in Delhi as AQI turns 'poor'; rainfall likely in most states
Delhi's air quality deteriorated to the poor category amid hot and humid weather, while an active monsoon pattern is set to bring heavy rainfall, thunderstorms and gusty winds to several states
 "Cloudy skies in Delhi as AQI turns 'poor'; rainfall likely in most states")
Delhi cloudy conditions prevail as AQI improves to 'moderate' level
Although the India Meteorological Department (IMD) issued a yellow alert for the day, only isolated areas of Delhi received light rain during the night between Friday and Saturday
 "Delhi cloudy conditions prevail as AQI improves to 'moderate' level")
Delhi air quality improves to moderate after 157 days, AQI at 119
The 24-hour average Air Quality Index (AQI) stood at 119, the lowest recorded since October 9, 2025, when the AQI had stood at 99 in the same category
 "Delhi air quality improves to moderate after 157 days, AQI at 119")
Delhi remains most polluted city in 2024-25, Patna second: Report
While historically less polluted, Bengaluru and Chennai showed signs of air quality deterioration during the winter months, a new vulnerability trend
 "Delhi remains most polluted city in 2024-25, Patna second: Report")
Delhi air quality remains poor as summer heat arrives early in the capital
Even as summer heat arrives early in Delhi, pollution stays high with AQI in 'poor' range. Experts warn prolonged exposure may affect children, elderly, and those with respiratory issues
 "Delhi air quality remains poor as summer heat arrives early in the capital")
Delhi AQI stays 'poor', temperatures above normal; mercury to cross 35°C
Overall AQI at 208 with 25 stations in 'poor' category; warm night and cloudy skies push minimum temperature well above normal across the capital
 "Delhi AQI stays 'poor', temperatures above normal; mercury to cross 35°C")
Delhi chokes on poor air as city records hottest early March in 50 yrs
AQI crossed 200 in Delhi after three days of 'moderate' air quality as IMD data showed the city recorded its hottest first week of March day in 50 years
 "Delhi chokes on poor air as city records hottest early March in 50 yrs")
Delhi AQI slips to 'poor' category as pollution levels rise again
Overall AQI climbs to 227 with most monitoring stations in poor category; Mundka records 'very poor' air quality despite clear skies and warm conditions
 "Delhi AQI slips to 'poor' category as pollution levels rise again")
Delhi AQI remains 'moderate' as surface winds keep pollution in check
Overall air quality index stands at 151 with most monitoring stations in moderate category; clear skies and warm conditions expected across the national capital
 "Delhi AQI remains 'moderate' as surface winds keep pollution in check")
Delhi air quality improves to 'moderate' aided by strong surface winds
Air quality stands at 135 in moderate category; strong surface winds and clear skies likely to aid further dispersal of pollutants across the national capital
 "Delhi air quality improves to 'moderate' aided by strong surface winds")