[hondatoyotafan]

Had to go to Gurgaon on a business trip in November, the air quality was super bad and it reminded me of the internship i did at a cement factory during my undergrad days.

The only difference was that the air in the entire city felt like that of the cement factory.

[binoyyj]

Mumbai recorded AQI worse than Delhi on Sunday.

https://indianexpress.com/article/ci...umbai-8383814/

"Being an island city, Mumbai’s AQI is determined by winds blowing from the sea. Usually, reversal in wind direction would take place every 4-5 days. This year, however, we have seen the same occurring after a gap of 15 days. During this period, surface winds blow at a slow speed, and later, when the sea breeze hits the city after two weeks it disperses all pollutants suspended in the air”

"Mumbai’s AQI will again improve following a reversal of winds after two weeks, this pattern would continue till end of winter. Usually, during winter, the breeze is slower in speed than usual due to which particulate matters stay suspended in the lower atmosphere in the form of mist and haze leading to poor AQI"

[ShankarG]

I went to Delhi for 3 weeks in Dec - Jan and it was tough to manage in the AQI. Smog ensured that we couldn't go outdoors. I remember 15-20 years back when Delhi winters were an experience of a lifetime and attracted many visitors to the heart of India. Sadly now we ourselves try to find a reason to exit Delhi during Diwali and New year.

The problem in Delhi is not just for Delhi but for the entire north India. It is just that AQI monitors are in limited numbers even in cities like Chandigarh, Dehradun, Lucknow etc. Biggest problem is not just automobiles, but the apathy of local municipality to control dust. More than 90% of Delhi roads have loose dust on the sides which is never addressed. Government surely doesn't have the will to do anything about it. Walk into any government or minister's office, there are countless air purifiers in every corner adding to their privileges.

With time, I feel an urge to move to a different part of the country like Pune. Feel sorry for kids and aged people.

[v1p3r]

Originally Posted by pioneer_rags

With respect to Air Pollution, we are only following the research done by USEPA. I am not sure if we have a research institute for Air Pollution. For example, the very idea of PM2.5 measured in micrograms per cubic meter is based on historical data on pollution in the US. Laser instruments which measure PM 2.5 actually measure the number of particles in the range of 0.1 to 2.5 microns in a given volume of air and the density of particles are taken based on data from the US city and then converts into micrograms per cubic meter. Also, the material composition of PM 2.5 in Delhi might be different from LA or Bangalore or Mumbai or Bhopal or Raipur.

This is only partially correct and slightly misleading. Let me clarify:
- US EPA does not use laser particle meters. Those are used by lower-cost monitors. EPA uses beta-attenuation monitors and other such tech, where each monitor can cost upto $ 1 m.
- Laser counters have been proven to be very accurate - 99% - as long as they are maintained well and calibrated correctly.
- Unless the particle is very toxic (mercury, anthrax) it makes little difference. 99% of these particles are carbon or hydrocarbons. The microparticle goes through the bloodstream, lungs, and sometimes blood-brain barrier. Foreign particles in such situations act as carcinogens, examples being asbestos and microplastics, both of which are not inherently toxic.

There is no need to do more research. The whole world has researched it and realised the harm. The Chinese cracked down and nearly ended the pollution menace. In India, it is a lack of political will coupled with apathy. There are also some 'researchers' with vested interested making good money doing nothing, both in government as well as in the private sector. If pollution went away, they would be unemployed.

Originally Posted by maddy42

A wonderful graph on population density will open the eyes of a lot of us who are not from the region. Delhi and the surrounding regions and states have almost 70% of our population density in comparison to the rest of the country.

This graph appears to be incorrect. Delhi is less than half the population density of Mumbai, and less than even Kolkata or Chennai.

[kika]

People say the the pollution is due to burning crops and not due to vehicles. Can delhites share some knowledge on this?

[akp666]

While I agree the situation in Delhi is bad, with compounding effect of the weather patterns and stubble burning let's also talk more about Mumbai or other equally polluted big cities. Not visiting Mumbai in their supposed winters as well.

[alpha1]

I stay in Mumbai, I was in Delhi last week. I have also stayed for a long time in Pune (and happened to be there in Dec last week).
My observations:
1) Pune is markedly less polluted compared to Delhi & Mumbai? How do I know? The strength of the sunlight reaching ground and the "azure-ness" skies when it is not cloudy or foggy.
2) Mumbai skies appears slightly lesser polluted version of Delhi during winters, but clears out considerably during summers and monsoons. Not so in Delhi.
3) AQI of most Indian cities is horrible because of dust (infra / construction related mostly), industrial/commercial establishments (furnaces, boilers, generators) using poor quality fuels, commercial and persona vehicles emissions.
4) The northern part of the country is also subject to dusty winds blowing in from desert areas, barren lands (indo-gangetic plains alluvial particles are really fine and stay suspended for long)
5) In addition to above, Delhi is also hit by stubble burning smoke from the neighboring areas. This is seasonal only.

Originally Posted by kika

People say the the pollution is due to burning crops and not due to vehicles. Can delhites share some knowledge on this?

Answered above.

@akp666 & others: To the people posting screenshots of poor air quality in XYZ city compared to Delhi please draw this comparison during the stubble burning season.

[v1p3r]

What do you do if your pollution sensors read high numbers? Why, you move them to cleaner parts of the city, of course!

https://www.hindustantimes.com/citie...983970144.html

[am1m]

Originally Posted by v1p3r

What do you do if your pollution sensors read high numbers? Why, you move them to cleaner parts of the city, of course!

Sad, but can't say this is unexpected.

The first step to solving a problem is acknowledging there is a problem and measuring the size of the problem. But before that there will be these stages- blame game, "xyz city is still better than abc", "why is no one talking about 123 which is worse", (which has started on this thread too!), "and what about this cause, why does everyone only target that cause which happens only once a year, this is political!" (again, prime example of that on another pollution-related thread ) etc etc.

Then only when the problem becomes too large to ignore, when the families of even those who can travel everywhere in ac cars and afford air purifiers at home start showing the health effects, that's when the accurate measuring stage at least will start. I'm afraid it'll be years before we even start solving this problem in any of our cities.

[alpha1]

Originally Posted by am1m

Then only when the problem becomes too large to ignore, when the families of even those who can travel everywhere in ac cars and afford air purifiers at home start showing the health effects, that's when the accurate measuring stage at least will start. I'm afraid it'll be years before we even start solving this problem in any of our cities.

The issue is that the current levels of pollution will show its adverse effects over few decades. For an individual that is too long term on the horizon.
As with everything else in world: the most efficient way of voting is through wallet and unless people in large numbers stop accepting jobs in polluted cities, nothing is going to change.

[locusjag]

Originally Posted by alpha1

unless people in large numbers stop accepting jobs in polluted cities, nothing is going to change.

If we are all able to live in far flung areas as we please and still work, the carbon footprint of products and services being delivered per household will shoot up. This will be bad for the planet as a whole since greenhouse gas emissions will increase, while it will mitigate the particulate matter emission problem in our densely populated cities.

Part of the reason why developed countries have such high greenhouse gas emissions and carbon footprints per capita is that they have developed rural areas and not everyone lives in urban clusters. The flipside of this is - lots and lots of diesel gets spent in sending goods and services to where they live.

Ugly, dense and PM2.5 clogged as they may be, India's urban clusters are highly energy-efficient logistically and good for the planet in terms of greenhouse gas emissions.

Illustrated simply from another perspective, I can ride my motorcycle 500 metres and hit the local kirana store for supplies; but back in Connecticut, I had to drive my car 5 miles to hit the local convenience store to get a gallon of milk.

[akp666]

Originally Posted by alpha1

@akp666 & others: To the people posting screenshots of poor air quality in XYZ city compared to Delhi please draw this comparison during the stubble burning season.

Done. I wish I had screenshots still saved during the stubble burning days. Will do that when it all comes back to haunt us next season. My only point is, take stubble burning out of the equation and Delhi is almost at par w.r.t pollution and it's effects as other major Indian cities. It just makes news because it is a thing now. The screenshots do not mean not to belittle people calling out Delhi and it's pollution. Infact it helps because the negative publicity makes the Delhi govt get off it's ass and take some measures at least (close down schools/Odd-even/banning BS 2 & 3 cars) while the other cities continue on quietly. Not getting into the debate whether the said measures are effective or not, but at least they try. The effect pollution has on one's health is the same, no matter how much sunlight reaches the ground. It is the same toxic particles entering one's lungs. A 200 AQI in Pune with sunlight vs 240 AQI in Delhi with fog cover sadly will kill people almost the same. The issue is not to only talk about delhi in a few days of the year, or single out a few cities. The pollution problem that plagues the major cities needs to be dealt with asap before it chokes us all, and each city needs separate measures keeping in mind their location, wind patterns and climate.

Coming back to Delhi. Until the issues with the paddy crops in Punjab is not sorted, including the timing of the harvest, this problem will never go away. It will get only worse; because the wind patterns and the climate will not change. Only humans have to take that into account and make changes accordingly.

[volkman10]

Three Indian cities among world's 10 most polluted after Diwali 2023.

Delhi was joined in the top 10 by Kolkata, which came in fourth with an AQI of 196, while Mumbai was eighth with an AQI of 163.

The national capital took, as it often does, the top spot. It had an air quality index (AQI) figure of 420, putting it the 'hazardous' category, according to Swiss group IQAir.


Link