Delhi-NCR air quality slipped to unhealthy between October 1 and 3. Students facing exams and placements feel confused by viral hacks. This explainer separates myth from science for quick decisions. It covers CPCB bands, masks, jog timing, indoor fixes, and smarter, low-exposure commutes.
Fine particles damage lungs and slow cognition, hurting revision stamina and test performance. Many apps flag ‘unhealthy’ when particulate levels surge. India’s official scale is the Central Pollution Control Board bands. Use both signals this week to plan study schedules, workouts, and travel windows.

Link actions to the AQI band, not panic. When values move from Moderate to Poor, limit outdoor time and intensity. Very Poor days demand strict exposure cuts. Run a HEPA purifier in study rooms, matched to room size, and keep doors closed during peak hours.
| AQI band | Student action |
|---|---|
| Good/Satisfactory | Outdoor sports, ventilate. |
| Moderate | Short outings; avoid traffic. |
| Poor | N95; skip jogs; windows shut. |
| Very Poor/Severe | Stay in; run HEPA; brief cross-vent. |
Cloth and surgical masks leak and miss fine particles. Choose N95 or FFP2 without exhalation valves. Fit matters more than logos. Press the nose clip and check for edge leaks. Replace when soiled or after heavy exposure, and wear it door to door.
Morning air is not cleaner during smog episodes. Night inversions trap pollution until sunlight breaks them. Check live AQI and wind before runs. Prefer indoor cardio or afternoon walks on better hours. Plants and wet towels do not remove PM2.5; use a HEPA purifier.
Plan low-traffic routes, even if slightly longer. Sit away from open windows on buses. Keep a reliever inhaler and spacer if prescribed, plus a written plan. Rinse nose with sterile saline after travel. Save intense study blocks for cleaner hours shown by reliable AQI apps.
For the next few days, treat exposure like a variable you can control. Check AQI before leaving, mask correctly, ventilate strategically, and run a right‑sized HEPA purifier while revising. Small changes protect lungs and focus during a crucial season. Share this guide with your class group.