Context:
World Air Quality Report 2024 ranked India as the 5th most polluted country globally.
World Air Quality Report:
- Released by – IQAir, a Swiss air quality technology company.
- Data Coverage – Analyzed data from over 40,000 air quality monitoring stations across 138 countries, territories, and regions.
Key Highlights:
- Only 17% of global cities met the WHO air pollution guideline of PM2.5 concentration ≤ 5 µg/m³.
- 126 out of 138 countries exceeded the WHO annual PM2.5 guideline.
- Most Polluted Countries – Chad, Bangladesh, Pakistan, Democratic Republic of the Congo and India
- Cleanest Regions –
- Oceania – 57% of cities met WHO guidelines.
- Mayaguez (Puerto Rico) – Cleanest metropolitan area
- Pollution Sources – Crop stubble burning, vehicular emissions, industrial discharges, and construction dust were major contributors.
- Wildfires in the Amazon rainforest significantly impacted air quality in Latin America
India-Specific Insights:
- India ranked 5th among the most polluted countries, a slight improvement from its 3rd place position in 2023
- 13 out of 20 most polluted cities found in India
- Byrnihat (Meghalaya) recorded the highest PM2.5 concentration globally
- Delhi positioned as the world’s most polluted capital for the 6th consecutive year.
- Improvement – India’s average PM2.5 concentration decreased by 7% from 2023
Source: DTE
Previous Year Question
In the context of WHO Air Quality Guidelines, consider the following statements:
1. The 24-hour mean of PM2.5 should not exceed 15 μg/m³ and annual mean of PM2.5 should not exceed 5 μg/m³.
2. In a year, the highest levels of ozone pollution occur during the periods of inclement weather.
3. PM10 can penetrate the lung barrier and enter the bloodstream.
4. Excessive ozone in the air can trigger asthma.
Which of the statements given above are correct?
[UPSC Civil Services Exam – 2022 Prelims]
(a) 1, 3 and 4
(b) 1 and 4 only
(c) 2, 3 and 4
(d) 1 and 2 only
Answer: (b)
Explanation:
Statement 2 is not correct:
As ozone concentrations increase above the guideline value, health effects at the population level become increasingly numerous and severe. Such effects can occur in places where concentrations are currently high due to human activities or are elevated during episodes of very hot weather
Statement 3 is not correct:
PM10 particles are small enough to pass through the throat and nose and enter the lungs. PM 2.5 particles are so small they can get deep into the lungs and into the bloodstream.