Revision summary
All three megacities pollute, but Delhi is landlocked and winter-trapped. Himalayan-plain geography and low mixing height hold smoke in the breathing zone. NCR sprawl, dust, and Punjab–Haryana stubble add a regional plume Mumbai and Kolkata do not share in the same way. Mumbai’s sea breeze and Kolkata’s bay and monsoon rain dilute more often. Delhi’s crisis is therefore geography plus regional sources, not only city size.
Model answer
Flow diagram
flowchart TD L[Landlocked Gangetic basin] --> T[Winter inversion trap] H[Himalaya weak wind] --> T S[NCR vehicles dust industry] --> T F[Farm fire plume] --> T T --> D[Severe Delhi smog] C[Coastal sea breeze rain] --> M[Mumbai Kolkata dilution]
Conclusion
- Delhi needs regional action on farms, NCR industry, dust, and winter transport, because city-only odd–even rules cannot beat a landlocked inversion.
Delhi’s air is more serious than Mumbai’s or Kolkata’s mainly because of inland location, winter inversion, Himalayan-plain trapping, and a surrounding farm-and-town smoke ring. The two older port megacities have the sea and, for Kolkata, heavier rains as natural vents. Emission control must therefore be regional for Delhi, not only municipal.
Quick related
Students also ask
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The states of Jammu and Kashmir, Himachal Pradesh and Uttarakhand are reaching the limits of ecological carrying capacity due to tourism. Critically evaluate.
Next question on this syllabus topic (2015 · Q17). View answer →
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Is Delhi more polluted only because it has more cars?
Cars matter, but trapping weather and regional farm and NCR smoke make the same car worse than on a windy coast.
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Are Mumbai and Kolkata free of bad air?
No. They have serious local pollution. They are less often locked in a winter smog bowl like Delhi.
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