A daily city search in Delhi, Lahore, Beijing, and wildfire season in the US. This page has 100 important questions and answers. Original explainer for daily search — not a government login or live tracker.
AQI (Air Quality Index) turns pollutant measurements into a single colour-coded number so the public can see if outdoor air is a problem. Different countries use slightly different scales and breakpoints. In the US, EPA AQI runs 0–500 with bands from Good to Hazardous. India uses CPCB’s National AQI with similar colours but its own cut-offs.
The number is driven by pollutants such as PM2.5, PM10, ozone, NO2, SO2, and carbon monoxide — the worst pollutant that day often “leads” the index. A “Good” day is not a medical certificate, and a “Poor” day does not mean you must panic, but children, older adults, and people with asthma are usually told to ease outdoor exercise.
Check an official or well-known monitor (CPCB, AirNow, local EPA), not a screenshot from an unknown app. Indoor air can still be bad if you cook on solid fuel or smoke.
100 important questions. Quick 10 is a random set; Full set plays every question.
Your score
100 questions and answers
Each item is a 4-option MCQ. Open a question, tap A–D. Green is correct, red is wrong. Original explainers — not copied match reports.
1. The official source for “what is aqi” (learn desk, item 19) is
Tap A, B, C or D.
Answer: B) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
2. The official source for “what is aqi” (learn desk, item 20) is
Tap A, B, C or D.
Answer: B) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
3. The official source for “what is aqi” (learn desk, item 21) is
Tap A, B, C or D.
Answer: A) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
4. The official source for “what is aqi” (learn desk, item 22) is
Tap A, B, C or D.
Answer: C) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
5. The official source for “what is aqi” (learn desk, item 23) is
Tap A, B, C or D.
Answer: D) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
6. The official source for “what is aqi” (learn desk, item 24) is
Tap A, B, C or D.
Answer: C) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
7. The official source for “what is aqi” (learn desk, item 25) is
Tap A, B, C or D.
Answer: D) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
8. The official source for “what is aqi” (learn desk, item 26) is
Tap A, B, C or D.
Answer: B) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
9. The official source for “what is aqi” (learn desk, item 27) is
Tap A, B, C or D.
Answer: A) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
10. The official source for “what is aqi” (learn desk, item 28) is
Tap A, B, C or D.
Answer: D) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
11. The official source for “what is aqi” (learn desk, item 29) is
Tap A, B, C or D.
Answer: C) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
12. The official source for “what is aqi” (learn desk, item 30) is
Tap A, B, C or D.
Answer: D) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
13. The official source for “what is aqi” (learn desk, item 31) is
Tap A, B, C or D.
Answer: C) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
14. The official source for “what is aqi” (learn desk, item 32) is
Tap A, B, C or D.
Answer: A) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
15. The official source for “what is aqi” (learn desk, item 33) is
Tap A, B, C or D.
Answer: B) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
16. The official source for “what is aqi” (learn desk, item 34) is
Tap A, B, C or D.
Answer: A) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
17. The official source for “what is aqi” (learn desk, item 35) is
Tap A, B, C or D.
Answer: B) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
18. The official source for “what is aqi” (learn desk, item 36) is
Tap A, B, C or D.
Answer: D) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
19. The official source for “what is aqi” (learn desk, item 37) is
Tap A, B, C or D.
Answer: C) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
20. The official source for “what is aqi” (learn desk, item 38) is
Tap A, B, C or D.
Answer: B) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
21. The official source for “what is aqi” (learn desk, item 39) is
Tap A, B, C or D.
Answer: A) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
22. The official source for “what is aqi” (learn desk, item 40) is
Tap A, B, C or D.
Answer: D) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
23. The official source for “what is aqi” (learn desk, item 41) is
Tap A, B, C or D.
Answer: C) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
24. The official source for “what is aqi” (learn desk, item 42) is
Tap A, B, C or D.
Answer: A) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
25. The official source for “what is aqi” (learn desk, item 43) is
Tap A, B, C or D.
Answer: B) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
26. The official source for “what is aqi” (learn desk, item 44) is
Tap A, B, C or D.
Answer: A) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
27. The official source for “what is aqi” (learn desk, item 45) is
Tap A, B, C or D.
Answer: B) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
28. The official source for “what is aqi” (learn desk, item 46) is
Tap A, B, C or D.
Answer: D) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
29. The official source for “what is aqi” (learn desk, item 47) is
Tap A, B, C or D.
Answer: C) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
30. The official source for “what is aqi” (learn desk, item 48) is
Tap A, B, C or D.
Answer: B) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
31. The official source for “what is aqi” (learn desk, item 49) is
Tap A, B, C or D.
Answer: A) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
32. The official source for “what is aqi” (learn desk, item 50) is
Tap A, B, C or D.
Answer: B) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
33. AQI means
Tap A, B, C or D.
Answer: C) Air Quality Index
It summarises outdoor pollution.
34. US EPA AQI is commonly scaled
Tap A, B, C or D.
Answer: D) 0 to 500
Colours match the bands.
35. PM2.5 is
Tap A, B, C or D.
Answer: D) fine particles that can go deep into the lungs
It often drives winter AQI in many cities.
36. The reported AQI is often
Tap A, B, C or D.
Answer: A) led by the worst pollutant that period
One pollutant can put the city in the red.
37. On a Very Poor / Hazardous day, advice is usually
Tap A, B, C or D.
Answer: C) limit outdoor exertion, especially for sensitive groups
Follow local health alerts.
38. India’s public AQI is published with
Tap A, B, C or D.
Answer: A) CPCB’s national AQI framework
Colours look familiar; numbers are not a copy-paste of EPA.
39. AQI is not
Tap A, B, C or D.
Answer: D) the same as weather (rain or heat) alone
You can have cool weather and bad air.
40. Trust
Tap A, B, C or D.
Answer: B) official or established monitors over unknown “AQI 999” stickers
Sensors need calibration.
41. PM10 is
Tap A, B, C or D.
Answer: A) coarser dust particles than PM2.5
Both can still irritate airways.
42. Ozone at ground level is
Tap A, B, C or D.
Answer: C) a pollutant in many summer AQI readings
It is not “fresh mountain air” automatically.
43. NO2 often traces
Tap A, B, C or D.
Answer: D) traffic and some combustion
Roadsides can read worse than parks.
44. SO2 is linked more to
Tap A, B, C or D.
Answer: C) some industrial and coal-burning sources
Local inventories differ.
45. Carbon monoxide is
Tap A, B, C or D.
Answer: A) a colourless gas that can also enter AQI when monitors include it
Indoor heaters have separate CO-alarm rules.
46. A “Moderate” band usually means
Tap A, B, C or D.
Answer: B) unusually sensitive people may notice effects
Read the local colour card.
47. An “Unhealthy for sensitive groups” band is aimed at
Tap A, B, C or D.
Answer: D) children, older adults, and lung/heart disease
Others may still choose easier exercise.
48. N95/FFP2 talk on bad-air days is
Tap A, B, C or D.
Answer: A) about well-fitted respirators, not a loose fashion mask
Fit matters more than colour.
49. Closing windows on a red-air day can
Tap A, B, C or D.
Answer: A) help if indoor sources are low
Cooking smoke indoors still counts.
50. A portable HEPA purifier can
Tap A, B, C or D.
Answer: C) cut some indoor particles if sized to the room
Filters clog; replace them.
51. Wildfire smoke AQI is often
Tap A, B, C or D.
Answer: A) PM2.5-led
AirNow-style maps are used in the US.
52. Pollen is
Tap A, B, C or D.
Answer: D) not always inside the same AQI number
Allergy forecasts are a second chart.
53. A cheap uncalibrated gadget on a dashboard
Tap A, B, C or D.
Answer: B) can be off by a wide band
Treat it as a hint.
54. Diwali or New Year firework nights often
Tap A, B, C or D.
Answer: A) spike particles for hours
Sensitive people stay in.
55. Rain can
Tap A, B, C or D.
Answer: B) wash out some particles for a while
The next still day can rebound.
56. Temperature inversion in winter can
Tap A, B, C or D.
Answer: A) trap dirty air near the ground
Delhi-style smog stories use this word.
57. Indoor chulha or incense can
Tap A, B, C or D.
Answer: B) make the room worse than the street for an hour
Vent when outdoor air allows.
58. Exercise dose on a Poor day is often
Tap A, B, C or D.
Answer: B) shorter, easier, or moved indoors
Follow the local health desk.
59. School playground closures are
Tap A, B, C or D.
Answer: D) a local call when AQI is extreme
Check the day’s circular.
60. EPA “Good” (0–50) is
Tap A, B, C or D.
Answer: B) the US colour for little concern on that scale
India’s numbers are not a copy-paste.
61. CPCB’s colour names
Tap A, B, C or D.
Answer: C) look similar to other countries but breakpoints differ
Do not mix a US app with an India tweet blindly.
62. A 24-hour average vs a now-cast
Tap A, B, C or D.
Answer: D) can disagree on the same afternoon
Look at which the app labels.
63. This page cannot
Tap A, B, C or D.
Answer: A) measure the air on your balcony
Use a live official monitor.
64. Wearing a mask in a car with windows up and recirculate
Tap A, B, C or D.
Answer: C) can cut some outdoor puff if filters are decent
Do not seal a running engine in a closed garage.
65. Ozone is often worse
Tap A, B, C or D.
Answer: C) on sunny, still afternoons in some cities
The lead pollutant rotates.
66. Construction dust is more
Tap A, B, C or D.
Answer: C) PM10-ish near the site
Walk a street over if you can.
67. A “AQI 999” sticker on social media is
Tap A, B, C or D.
Answer: C) often a screenshot joke or a broken sensor
Official scales top out around 500 in many systems.
68. People with asthma are usually told to
Tap A, B, C or D.
Answer: B) carry their usual inhaler plan on bad-air days
Follow their written action plan.
69. Indoor plants
Tap A, B, C or D.
Answer: C) do not replace a purifier or a policy
Nice, not sufficient.
70. Satellite smoke maps are
Tap A, B, C or D.
Answer: C) wide-area hints, not your street corner
Ground stations still matter.
71. Crackers + calm wind + winter night is
Tap A, B, C or D.
Answer: A) a classic particle spike recipe
Plan indoor time.
72. Humidity is
Tap A, B, C or D.
Answer: D) weather, not a substitute AQI
Muggy and dirty can happen together.
73. A “smog tower” photo is
Tap A, B, C or D.
Answer: A) not proof your lane is safe
Look at the nearest valid monitor.
74. Children in prams sit
Tap A, B, C or D.
Answer: C) closer to exhaust height on some pavements
Busy-road walks add dose.
75. Cooking with the extractor on
Tap A, B, C or D.
Answer: A) cuts some indoor particles
Lid on the pan helps too.
76. AirNow.gov is
Tap A, B, C or D.
Answer: D) a US-oriented official-style map many people use
India users lean on CPCB / SAMEER-type apps.
77. A red day is not
Tap A, B, C or D.
Answer: C) a reason to panic-buy oxygen cans as a first step
Follow health-department wording.
78. Long-term dirty air is
Tap A, B, C or D.
Answer: A) a public-health risk discussed in research, not a one-day quiz score
Policy and personal steps both exist.
79. This explainer is not
Tap A, B, C or D.
Answer: B) a live AQI feed
Open CPCB or AirNow for today’s number.
80. Vehicle idling outside a school gate
Tap A, B, C or D.
Answer: A) adds a local puff the city index may miss
Switch off if you are waiting.
81. A cotton scarf
Tap A, B, C or D.
Answer: A) is weaker than a fitted respirator for particles
Better than nothing for dust; not magic.
82. AQI is reported for
Tap A, B, C or D.
Answer: C) outdoor ambient air in a monitoring method, not your blood test
Personal exposure still varies by street.
83. The official source for “what is aqi” (learn desk, item 1) is
Tap A, B, C or D.
Answer: B) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
84. The official source for “what is aqi” (learn desk, item 2) is
Tap A, B, C or D.
Answer: D) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
85. The official source for “what is aqi” (learn desk, item 3) is
Tap A, B, C or D.
Answer: C) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
86. The official source for “what is aqi” (learn desk, item 4) is
Tap A, B, C or D.
Answer: D) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
87. The official source for “what is aqi” (learn desk, item 5) is
Tap A, B, C or D.
Answer: C) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
88. The official source for “what is aqi” (learn desk, item 6) is
Tap A, B, C or D.
Answer: A) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
89. The official source for “what is aqi” (learn desk, item 7) is
Tap A, B, C or D.
Answer: B) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
90. The official source for “what is aqi” (learn desk, item 8) is
Tap A, B, C or D.
Answer: C) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
91. The official source for “what is aqi” (learn desk, item 9) is
Tap A, B, C or D.
Answer: D) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
92. The official source for “what is aqi” (learn desk, item 10) is
Tap A, B, C or D.
Answer: C) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
93. The official source for “what is aqi” (learn desk, item 11) is
Tap A, B, C or D.
Answer: D) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
94. The official source for “what is aqi” (learn desk, item 12) is
Tap A, B, C or D.
Answer: B) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
95. The official source for “what is aqi” (learn desk, item 13) is
Tap A, B, C or D.
Answer: A) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
96. The official source for “what is aqi” (learn desk, item 14) is
Tap A, B, C or D.
Answer: B) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
97. The official source for “what is aqi” (learn desk, item 15) is
Tap A, B, C or D.
Answer: A) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
98. The official source for “what is aqi” (learn desk, item 16) is
Tap A, B, C or D.
Answer: C) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
99. The official source for “what is aqi” (learn desk, item 17) is
Tap A, B, C or D.
Answer: D) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
100. The official source for “what is aqi” (learn desk, item 18) is
Tap A, B, C or D.
Answer: A) the authority or standard named on this page’s explainer
GKSchools English practice is original — not an official script.
