The Delhi air pollution measures that worked best changed emissions every day: CNG for buses, autos and taxis (1998-2002), cleaner fuel and BS-VI vehicles, the…
The Supreme Court ordered Delhi's whole bus fleet onto CNG by 2001. Autos and taxis followed, and the switch was complete for buses by 2002.
The first Metro line opened in 2002 and the network now spans about 400 km. It cuts emissions when it replaces car and bike trips.
Estimates for January 2016 range from 4-6% to 14-16% lower PM2.5. April showed no clear effect, and pollution jumped 57% the day after it ended.
Four stages of curbs on construction, trucks and generators as AQI rises. Since 2022 it acts on forecasts, but severe days still happen.
India jumped from BS-IV to BS-VI norms. Delhi already had BS-VI fuel from 2018, and Badarpur coal plant closed in 2018.
Annual AQI fell to 201 and severe days from 17 to 8. But December 2025 still averaged 351.
Secondary particles 27%, transport 23%, biomass burning 20%, dust 15%, industry 9%. CAQM approved 46 new monitors.
Pumps refuse fuel without a valid pollution certificate. From 1 November, non-BS-VI vehicles from outside Delhi are barred.
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