Context:
Air quality index (AQI), according to the Central Pollution Control Board (CPCB), is a measure of the concentration of eight pollutants — particulate matter (PM)10, PM2.5, nitrogen dioxide (NO2), sulphur dioxide (SO2), carbon monoxide (CO), ozone (O3), ammonia (NH3), and lead (Pb) — in the air at a monitoring location. A sub-index is calculated for each of these pollutants (not all may be measured at every station); and the worst among them is the AQI for that location. So, AQI transforms complex air quality data into an index we can understand.
Relevance:
GS III: Environment and Ecology
Dimensions of the Article:
- About Air Quality Index
- About National Ambient Air Quality Standards
- Delhi’s Uninhabitability Due to Air Pollution
About Air Quality Index
- National Air Quality Index was launched by the Prime Minister in April, 2015 starting with 14 cities to disseminate air quality information.
- The AQI has six categories of air quality, viz Good, Satisfactory, Moderately Polluted, Poor, Very Poor and Severe with distinct colour scheme. Each of these categories is associated with likely health impacts.
- AQI considers eight pollutants (PM10, PM 2.5, NO2, SO2, CO, O3, NH3 and Pb) for which (up to 24-hourly averaging period) National Ambient Air Quality Standards are prescribed.
About National Ambient Air Quality Standards:
- The mandate provided to the Central Pollution Control Board (CPCB) under the Air (Prevention and Control of Pollution) Act empowers it to set standards for the quality of air.
- National Ambient Air Quality Standards (NAAQS) were notified in the year 1982, duly revised in 1994 based on health criteria and land uses.
- The NAAQS have been revisited and revised in November 2009 for 12 pollutants, which include
- Sulphur dioxide (SO2),
- Nitrogen dioxide (NO2),
- Particulate matter having size less than 10 micron (PM10),
- Particulate matter having size less than 2.5 micron (PM2.5),
- Ozone,
- Lead,
- Carbon monoxide (CO),
- Arsenic,
- Nickel,
- Benzene,
- Ammonia,
- Benzopyrene
Delhi’s Uninhabitability Due to Air Pollution
Overview
- Problem Introduction: Delhi faces severe uninhabitability issues due to extreme air pollution in winter (October-February) and oppressive heat waves in summer (April-June). This analysis focuses on air pollution, specifically PM2.5 particles, which are detrimental as they penetrate deep into the lungs.
Air Quality Analysis
- Data Presentation: Over seven years (2017-2023), Delhi experienced merely two days of “healthy” air annually, with over half the year marked by air quality unfit for breathing.
- Lockdown Observation: Even during the 2020 lockdown, air quality showed only marginal improvement, indicating systemic issues.
Misconceptions and Realities
- Stubble Burning Impact: November data shows that even without stubble burning, Delhi’s air quality would still not meet the “very poor” standards. This points to stubble burning as a scapegoat used by political factions to avoid addressing core issues.
Internal Pollution Sources
- Major Contributors: An extensive 2023 report identifies local sources as half of Delhi’s PM2.5 pollution during winter, with vehicles contributing 58% through exhaust and mechanical wear.
Seasonal Worsening in Winters
- Meteorological Effects: Pollutant concentration is influenced by lower temperatures, reduced wind speed, and lack of rain in winter, trapping pollutants near the ground.
Health Impacts
- WHO Findings: Air pollution impacts nearly every organ, with PM2.5 and PM10 causing systemic inflammation and potential carcinogenic effects.
- Local Death Rates: Studies indicate a higher rate of deaths due to ambient PM pollution in Delhi compared to the national average, highlighting severe health risks.
Socioeconomic Disparities
- Class-Based Impact: The poorer communities, like children from less affluent neighborhoods, are exposed to significantly higher levels of PM2.5, potentially reducing life expectancy compared to their wealthier counterparts.
-Source: The Hindu
