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#DelhiChokes: Pollution level touches 999, against safe limit of 60

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With a dense cluster of smog shrouding the National Capital Territory of Delhi for the past two days, the city has become a veritable gas chamber. On Wednesday, the PM 10 level in Delhi shot through the roof to cross 1,000-plus at places, as per the data provided by the Delhi Pollution Control Committee (DPCC).  On the World Air Quality Index, at least three localities in Delhi showed an alarming 999 of PM 10 (recorded at 1300 hrs, November 8) — RK Puram, ITO, and Punjabi Bagh.  The PM 2.5 readings were found to be around 800-900. Of the NCR territories, Faridabad fares the worst at 890 while Gurgaon was around 400. And the data for Noida and Ghaziabad in the state of Uttar Pradesh was not available.

world air quality index
Chart showing air pollution levels

To put things in perspective, for a clearer understanding of the magnitude of this grisly pollution, the PM 2.5 level of Delhi on normal days is around 122 and of Beijing is 85. As a whole, Delhi recorded an average PM 10 volume of 260 in 2016, which was four times above the safe level. Pollution level up to 60 is considered safe, while anything beyond 200 is considered very poor. PM 10 is particulate matter 10 micrometers or less in diameter, and PM 2.5 is particulate matter 2.5 micrometers or less in diameter. A reading greater than 400 is considered severe and may cause respiratory impact even on healthy people, and serious health impacts on people with lung/heart disease. The health impacts may be experienced even during light physical activity. Now imagine what would be the dreadful impact of 999!

Yesterday the particulate matter (PM2.5) level in Delhi reached 710 – which is 11 times more than the recommended safe limit by WHO – and the Indian Medical Association declared it a medical emergency.

world air quality index
Delhi topped the chart as the most polluted capital city in the World Air Quality Index

As of today, Delhi is the most polluted city on the World Air Quality Index. The only others who scored the same alarming 999 in PM 10 were Merzifon in Turkey and the ghost city of Eerduosi in China. Ardahan in Turkey was next at 890. Of the otherwise usual culprits who rank over Delhi on the WHO annual list, either they ranked much low (such as Xintai in China at 181), or data was not available (like for Gwalior and Allahabad, India or Riyadh Saudi Arabia). On an annual basis, Delhi ranks 11th on the WHO list of almost 3,000 towns and cities in 103 countries.

There seems no respite for a couple of more days as advisories are being issued to avoid going outdoors as much as possible. Coupled with winter mist, the smog is reducing visibility and increasing the risk of road accidents.

What is World Air Quality Index?

World Air Quality Index is a Beijing based project that spreads awareness about air pollution and fetches real-time data from various organizations and air pollution monitoring stations. The data published on the World Air Quality Index is real-time and therefore invalidated at the time of publication. However, in order to ensure a high level of accuracy for each AQI figures, several machine learning processing solution are used. For instance, data consistency is verified, in real-time, with the neighbor stations, allowing to automatically detect defective monitoring stations, and remove them, if needed, from the map. It claims the data for Delhi on the map was based on real-time ambient air quality data of the Delhi Pollution Control Committee.

As of February 2017, real-time Air Quality information is available for than 9,000 stations in 800 major cities from 70 countries, thanks to the huge effort from the world EPAs (Environmental Protection Agencies). There are currently more than 20,000 known air quality monitoring stations in the world, out of which more than 9,000 are published on the World Air Quality Index project. In order to keep a high level of consistency, only stations with particulate matter (PM 2.5 and PM 10) readings are published. The AQI standard for every single published station is based on the US EPA Instant-Cast standard.