| Introduction: Contextual Introduction Body: Impact of La Nina on air quality and how climate change is contributing to polluting pattern Conclusion: Way forward |
La Niña, a climate phenomenon associated with cooler sea surface temperatures in the central and eastern Pacific Ocean, typically leads to stronger monsoons in India. However, its delayed onset in 2024 and the late retreat of the monsoon have raised concerns about worsening air quality in North India, particularly in urban centers like Delhi.
Impact of La Niña on Air Quality in North India
- Prolonged Winter and Temperature Inversions: During La Niña years, colder-than-average temperatures in North India lead to longer winter seasons. This can enhance temperature inversion THAT prevents pollutants, such as particulate matter (PM2.5 and PM10) and nitrogen oxides, from dispersing, thus exacerbating air pollution in urban centers like Delhi.
- Increased Humidity and Fog: La Niña conditions tend to bring higher humidity and more fog in North India during winter. Fog traps pollutants near the surface, further worsening air quality.
- Stubble Burning and Wind Patterns: The La Niña-induced delay in monsoon withdrawal can affect the timing of agricultural practices, such as stubble burning, which is a major source of pollution in North India during autumn.
Climate Change and Unpredictable Pollution Patterns
- Slower Monsoon Withdrawal: The delayed retreat of the monsoon, a feature increasingly observed in a warming climate, leads to extended periods of high humidity and stagnant surface winds. This reduces the atmospheric mixing of pollutants and increases the concentration of PM2.5 and PM10 levels, particularly in urban areas like Delhi.
- Impact on Pollutant Behavior: Climate change influences atmospheric circulations, such as the ENSO (El Niño-Southern Oscillation), leading to unpredictable changes in wind patterns and the behavior of pollutants over long distances. The dominance of north-north-westerly winds in the absence of La Niña means that pollutants from stubble burning in Punjab and Haryana are likely to accumulate in Delhi, worsening air quality in early winter.
- Intensified Urban Heat Islands: In cities like Delhi, climate change exacerbates the urban heat island effect, leading to higher temperatures that increase the formation of secondary pollutants like ozone and smog. This worsens air quality during both winter and summer months.
- Extended and Severe Winters: La Niña is known to bring longer and more severe winters, which, when combined with climate change-induced variability, could lead to extended periods of poor air quality.
Conclusion
Policymakers must adopt a more holistic approach, addressing not only local emissions but also broader meteorological and climatological factors that influence air quality. A health-centric strategy focused on managing PM2.5 levels and better coordination across airsheds is essential for effectively mitigating the impacts of air pollution in the region.
