A recent study published by the Indian Institute of Tropical Meteorology (IITM) and the National Institute of Advanced Studies (NIAS) has suggested that air quality in India could be influenced by the El Nino and La Nina climate patterns.
- The study analyzed air quality data from major Indian cities during the winter of 2022 when an unusually long and intense La Nina event was underway globally.
- It found anomalous wind patterns that led to cleaner air in northern India but worse air quality in western and southern cities like Mumbai and Bengaluru.
- The research highlights the impact of global climate phenomena on local environmental conditions and the need to understand these linkages.
La Nina and Its Influence on Indian Air Quality
- La Nina refers to the large-scale cooling of ocean surface temperatures in the central and eastern equatorial Pacific Ocean, coupled with changes in the tropical atmospheric circulation.
- It is one half of the El Nino-Southern Oscillation (ENSO) cycle, with El Nino being the warm phase.
- La Nina alters weather patterns across the globe, including the Indian monsoon, and generally lasts 9-12 months.
- As per the study, the record-breaking La Nina event in its third year (2022 winter) impacted wind patterns over India:
- The winds blew from north to south instead of the northwesterly direction seen usually during winter.
- This led to the transport of agricultural waste pollution from Punjab/Haryana towards western and southern India rather than Delhi.
- Delhi and surrounding regions saw improvement in air quality while Mumbai and Bengaluru recorded higher PM2.5 levels.
- Northern cities cleaner than western/southern cities, reversing the normal trend.
- The study states that La Nina’s influence led to wind direction changes.
- Agricultural crop waste pollution got transported southwards from Punjab/Haryana due to northerly to southerly winds.
La Nina Event of 2022
- The La Nina weather pattern prevailed for an unusually long duration of 3 consecutive years – 2020 to 2023.
- This rare “Triple Dip” La Nina intensified in its third year (2022) to become a record-breaking event as per the World Meteorological Organization (WMO).
- The WMO has estimated this triple-dip La Nina among the strongest events over the past 70 years.
- Its persistence over 3 years had widespread impacts on global ocean and atmospheric conditions.
- As per the study, there might be an accumulative effect of long-lasting La Nina leading to the noticeable changes in India’s wind patterns.
Implications of Findings
- Highlights that South Asian climate and extreme weather events are now being influenced by Pacific Ocean temperature anomalies.
- India’s air quality is linked with larger climate systems and is affected by climate change.
- Need better air pollution forecasting by factoring global climate phenomena like ENSO.
- Climate mitigation policies must consider such teleconnections to better adapt for future climate risks.
Recent Developments
- In December 2022, India’s National Oceanic and Atmospheric Administration (INCOIS) reported that La Nina conditions have peaked and will decline gradually after the usual January peak.
- However, the World Meteorological Organization stated in January 2023 that La Niña remains firmly in place and could re-intensify to become a rare 4-year long event (2020-2024).
- In February 2023, the India Meteorological Department (IMD) also indicated that La Nina conditions have not yet fully dissipated and some impacts could persist.
- A new real-time air quality and greenhouse gas monitoring network called CityAir was launched in Hyderabad and Vijaywada by a start-up in collaboration with academic institutes in February 2023.
- The network uses state-of-the-art sensors to give hyperlocal air pollution data to allow recording of pollution episodes during specific wind flows.
- Government policy think-tank NITI Aayog has planned an initiative called the Clean Air Excellence Awards and Conclave in March 2023.
- It aims to incentivize cities to achieve air quality standards through innovative policy implementation by recognizing excellence in air quality management.
- In March 2023, reports stated that the Commission for Air Quality Management for NCR has directed states to ensure bio-decomposer usage for stubble management before the 2023 paddy harvesting season.
- This proactive measure aims to reduce seasonal air pollution from post-harvest farm fires during the next winter season.
Further Analysis
- Links between La Nina and India’s air quality as suggested by the latest study merit more research using emissions inventories modelling.
- Findings underline that climate phenomena have local environmental impacts making interdisciplinary climate studies critical for evidence-based policymaking.
- As extreme climate events rise, monitoring La Nina connections with air pollution can assist governments tackle seasonal pollution efficiently through appropriate action.
