The Good Air blog
Air pollution and weather, explained clearly and sourced properly. Seasonal guides, news explainers and data from official monitoring networks.
Data stories · 19 Oct87 cities had dirtier air than Delhi this October. Most were in Indonesia and MalaysiaGood Air ranked 467 cities in 7 Asian countries by October 2026 PM2.5 from government monitors. The 25 most polluted are all in Indonesia; Delhi is 88th.- Data storiesAfter the monsoon, Maharashtra's air got worse four times as fast as Delhi'sWe compared 219 Indian cities before and after the 2026 monsoon left. Maharashtra's median AQI doubled, all 34 cities worse; Delhi NCR's rose 25%.
- GuidesHow to improve indoor air quality at home, and when to open the windowsHow to improve indoor air quality at home: cut the sources, ventilate when the outdoor AQI is low and filter the rest. Plus when to open the windows.
- NewsKalimantan haze: Central Kalimantan's air turns hazardous as smoke drifts over JakartaKalimantan haze update, 18 October 2026. Eight Indonesian cities and regencies hit hazardous ISPU, led by Kotawaringin Timur at 714.
- ExplainersWhat is ISPU? Indonesia's air quality index, and how it compares with the US AQIWhat is ISPU? Indonesia's official air quality index runs from Baik to Berbahaya. The five levels, what each means, and why it reads lower than the US AQI.
- NewsSoutheast Asia haze 2026: Singapore's PSI hits 192 as Malaysia shuts schoolsPeat fires in Sumatra and Kalimantan pushed Singapore's PSI to its 2026 high and shut Malaysian schools. What is happening and how to stay safe.
- Data storiesWhat time of day is Delhi's air cleanest? Our hourly data says early afternoonDelhi NCR's air was cleanest from noon to 5 pm and dirtiest late at night in our hourly data for 10 to 17 October 2026. When to walk, run and open windows.
- NewsNor'easter hits the Outer Banks: Hatteras visitors ordered out, NC 12 expected to close, 2 to 4 feet of floodingA nor'easter brings 50 mph gusts, waves to 14 feet and 2 to 4 feet of flooding to the Outer Banks from 17 October. Who must leave, NC 12 and the worst tides.
- GuidesPollution cough and sore throat: why smog makes you cough, what helps, and when to see a doctorA pollution cough comes from fine particles irritating your airways. How to tell it from a cold, what actually helps, and the warning signs that need a doctor.
- NewsTyphoon Champi: typhoon warning for Guam as a Category 2 storm heads for a near-direct hit on SundayTyphoon Champi is forecast to pass just south of Guam early Sunday 18 October as a Category 3 typhoon. Warnings, COR 1, rain, surge and shelters.
- NewsSanta Ana winds: Norte Fire forces 16,000 from homes as red flag warnings, heat and power shutoffs run through SaturdaySanta Ana winds in October 2026: the Norte Fire, 70,000 customers without power, red flag warnings and 95°F heat in Southern California until 17 October.
- SeasonalDiwali 2026 and air pollution: firecracker rules and how to protect your familyDiwali is on 8 November 2026. Are firecrackers allowed in Delhi NCR? The latest Supreme Court hearings, green crackers, and how to protect your family.
- SeasonalDhaka's smog season is back: why the air gets worse every winter, and how bad it getsDhaka air pollution is climbing into winter 2026, with the AQI reaching 213 on 6 October. Why the smog returns each year, when it peaks and how to stay safe.
- ExplainersFirst freeze of the season: what a freeze warning, freeze watch and frost advisory mean this weekendFreeze warning vs frost advisory: what each NWS alert means, where the first freeze hits the Plains and Midwest on 16 and 17 October, and how to protect plants.
- GuidesHow to protect children from air pollution: a parent's guide for smog and haze daysHow to protect children from air pollution on smog and haze days: when to keep them in, safe AQI levels for play, clean air at home, masks and school rules.
- ExplainersEl Niño 2026 could be the strongest on record: what it means for this winter's weatherEl Nino is heading for a strong to very strong peak this winter 2026-27, possibly the strongest since 1950. What it means for rain, heat and haze worldwide.
- NewsNortheast monsoon 2026 arrives in Tamil Nadu: onset, rain forecast and what to expect in ChennaiThe northeast monsoon 2026 is setting in over Tamil Nadu from 15 October. IMD expects normal October to December rain. Forecast, warnings and Chennai outlook.
- NewsRain and hail over Delhi NCR: will the storm clean the air, and for how long?Rain and hail on 14 and 15 October 2026 should briefly reduce Delhi pollution, but IMD expects dry weather from 16 October, and the smog usually returns.
- SeasonalLahore smog season 2026: when it starts, how bad it gets and what Punjab is doingLahore's smog season runs from October to February and peaks in November. Where the air stands on 15 October 2026 and what Punjab is doing about it.
- ExplainersPM2.5 vs PM10: what's the difference, and which one should you worry about?PM10 is coarse dust up to 10 micrometres; PM2.5 is fine smoke and soot up to 2.5. PM2.5 vs PM10 explained, with safe levels and today's examples.
- GuidesWhat size air purifier do you need? CADR and room size, explained for smog seasonMatch an air purifier's CADR to your room: at least two-thirds of the floor area in sq ft, or equal to it for heavy smoke. Worked examples for Indian homes.
- SeasonalHanoi's pollution season has begun: why the haze is back and how long it lastsHanoi's air reached US AQI 221 on 14 October 2026 as the smog season began. What causes it, how long it lasts, and what to do on bad days.
- GuidesN95 vs KN95 vs FFP2: which mask actually protects you from smog and haze?N95, KN95 and FFP2 masks all filter at least 94 to 95% of fine particles. For pollution, fit and a genuine label matter far more than which one you buy.
- NewsMalaysia haze school closures: which states are shut, and when schools reopenAll schools in Johor, Melaka and Negeri Sembilan were shut by haze on 14 October, plus nine districts. Who decides closures, and how to check.
