O₃ in India

Not emitted directly — formed when NO₂ and volatile organic compounds react in sunlight. Worst in summer afternoons. Different from the protective ozone layer.

Live O₃ levels — top Indian cities right now

Where O₃ comes from

• Vehicle exhaust (NO₂ + VOCs)
• Industrial solvents and paints
• Petrol vapours from refuelling
• Strong sunlight + high temperatures (precursor reaction)

How O₃ harms human health

• Coughing and sore throat
• Reduced lung function during outdoor activity
• Aggravated asthma
• Damages lung tissue with long-term exposure

What you can do

Reduce personal exposure with N95 masks during peak hours, run a HEPA purifier indoors, and switch to clean transport where possible. Push for systemic change: file an RTI, attend NCAP city consultations, demand transparent station data from your municipality.

Set O₃ alerts for your city →

Other pollutants