Air Quality Index (AQI) Today
Real-time air quality data for major Indian cities
0-50
51-100
101-150
151-200
201-300
301+
Understanding AQI Levels
Frequently Asked Questions about AQI
What is AQI and how is it measured?
AQI stands for Air Quality Index, a standardized indicator used to measure and report air pollution levels. It is calculated based on concentrations of major pollutants: PM2.5, PM10, ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2), and carbon monoxide (CO). Each pollutant is assigned a score, and the highest score becomes the overall AQI.
What are the health effects of different AQI levels?
Good (0-50): Minimal health impact. Moderate (51-100): Unusually sensitive people should limit outdoor activity. Unhealthy for Sensitive Groups (101-150): People with respiratory issues should reduce outdoor exertion. Unhealthy (151-200): Everyone may experience health effects. Very Unhealthy (201-300): Health alert — everyone may experience serious effects. Hazardous (301+): Emergency conditions — avoid all outdoor activities.
Which Indian cities have the worst air quality?
Major Indian cities face significant air pollution challenges. Delhi consistently ranks among the most polluted capitals globally, especially during winter months due to stubble burning, vehicle emissions, and weather conditions. Other cities with frequent poor AQI include Kolkata, Mumbai, Chennai, Bangalore, Hyderabad, Pune, and Ahmedabad. AQI worsens significantly from October to February.
How can I protect myself from poor air quality?
When AQI is unhealthy, wear N95 or N99 masks when outdoors, use air purifiers indoors, keep windows closed during high pollution hours, avoid outdoor exercise, use public transport to reduce vehicle emissions, plant indoor air-purifying plants, and monitor AQI levels regularly using our tracker to plan your outdoor activities.
What are the main causes of air pollution in Indian cities?
Major causes include vehicle emissions (the largest contributor in most cities), industrial emissions, construction dust, burning of crop residue (especially in Punjab and Haryana during October-November), coal-fired power plants, garbage burning, and seasonal weather conditions like temperature inversions that trap pollutants near the ground during winter months.
How is AQI data collected and verified?
AQI data is collected through a network of monitoring stations operated by the Central Pollution Control Board (CPCB) and state pollution control boards across India. Additional data comes from international monitoring networks like WAQI (World Air Quality Index project). Data is verified through calibration of monitoring equipment, cross-referencing multiple stations, and quality control protocols before publication.
