Dust Storms
Context: A recent dust storm, caused by strong westerly winds carrying dust from northwest India and Pakistan, led to a sharp spike in Delhi’s air pollution, pushing the AQI into the “poor” category and triggering political blame.
Important Pointers:
Definition: Dust storms are meteorological phenomena characterized by strong winds lifting large quantities of dust and sand from dry surfaces into the atmosphere, reducing visibility and degrading air quality.
Cause in Delhi (May 2025): Strong lower-level westerly winds advected dust from North Pakistan into Delhi, Punjab, and Haryana, triggered by a high north-south pressure gradient over Northwest India.
Wind Speeds: Surface wind speeds during the event reached 30–40 kmph, sufficient to lift and carry fine dust particles over large distances.
Air Quality Impact:
Delhi’s AQI rose from 135 (Moderate) to 292 (Poor) within 24 hours.
Unofficial readings touched 500+, falling under the ‘Severe-Plus’ category.
PM2.5 concentration reached 196.1 µg/m³, which is 13 times higher than WHO’s safe limit of 15 µg/m³ (24-hour mean).
Visibility Reduction: The dust storm significantly reduced visibility across Delhi, with IGI Airport reporting a lowest visibility of 1200 meters intermittently.
Geographical Path: Dust travelled from West Rajasthan → South Punjab → South Haryana → Delhi NCR, illustrating inter-state and transboundary pollution movement.
Meteorological Department Insight: The India Meteorological Department (IMD) attributed the event to an extreme weather system, not a localized anomaly.
Health and Environmental Concern: Exposure to high PM2.5 levels increases the risk of respiratory and cardiovascular diseases, especially in urban areas with high population density.